Numerical investigation of the three-dimensional dynamic process of sabot discard

HUANG Zhen-gui,WESSAM Mahfouz Elnaggar,CHEN Zhi-hua 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.7

The sabot discard process of an armor-piercing, fin-stabilized discarding sabot (APFSDS) is crucial for the flight stability of the projectile. In this paper, the sabot discard behavior after projectile ejection from the muzzle is investigated at Mach number 4.0 and angle ofattack of 0°. 3D compressible equations implemented with a dynamic unstructured tetrahedral mesh are numerically solved with a commercialcomputational fluid dynamics (CFD) code (FLUENT 12.0). Six-degrees-of-freedom (6DOF) rigid-body motion equations issolved with the CFD results through a user-defined function to update the sabot trajectory at every time step. A combination of springbasedsmoothing and local re-meshing is employed to regenerate the meshes around the sabot and describe its movement at each timestep. Computational results show three different separation processes during the sabot discard process. Furthermore, the aerodynamicforces of APFSDS are calculated, and the trajectories of the three sabots are illustrated through the numerical solution of 6DOF equations. The results of the present study agree well with typical experimental results and provide detailed parameters that are important for analyzingthe stability of the projectile. The present computations confirm that the numerical solution of the governing equations of aerodynamicsand 6DOF rigid-body equations are a feasible method to study the sabot discard processes of APFSDS.

Surface modification of poly(vinylidene fluoride) membrane with hydrophilic and anti-fouling performance via a two-step polymerization

Gui-E Chen,Li Sun,Zhen-Liang Xu,Hu Yang,Hui-Hong Huang,Yan-Jun Liu 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.12

The surface modification of poly (vinylidene fluoride) (PVDF) membrane was performed via a two-step polymerization reactions. Poly (acrylic acid) (PAAc) was first grafted onto the membrane surface for the preparation of PVDF-g-PAAc membrane, and then poly (ethylene glycol) 200 (PEG 200) was immobilized on the membrane surface by the esterification reaction for the fabrication of PVDF-g-PEGA membrane. Attenuated total reflectance (ATR) FTIR, X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), and protein adsorption, water flux, water content and dynamic contact angle were conducted to characterize the structures and performance of the resultant PVDF membranes. The experimental results showed that the adsorption of bovine serum albumin (BSA) on the PVDF-g-PEGA membrane decreased about 80% when the grafting ratio reached to 15 wt%, compared with the pristine PVDF membrane. Moreover, the water contact angle of the membrane dropped to 60.5o, while the membrane pore sizes remained little changed.

Anti-Angiogenic Activity of Gecko Aqueous Extracts and its Macromolecular Components in CAM and HUVE-12 Cells

Tang, Zhen,Huang, Shu-Qiong,Liu, Jian-Ting,Jiang, Gui-Xiang,Wang, Chun-Mei Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.5

Gecko is a kind of traditional Chinese medicine with remarkable antineoplastic activity. However, undefined mechanisms and ambiguity regarding active ingredients limit new drug development from gecko. This study was conducted to assess anti-angiogenic properties of the aqueous extracts of fresh gecko (AG) or macromolecular components separated from AG (M-AG). An enzyme-linked immunosorbent assay (ELISA) approach was applied to detect the vascular endothelial growth factor (VEGF) secretion of the tumor cells treated with AG or M-AG. The effect of AG or M-AG on vascular endothelial cell proliferation and migratory ability was analyzed by tetrazolium dye colorimetric method, transwell and wound-healing assays. Chick embryo chorioallantoic membrane (CAM) assays were used to ensure the anti-angiogenic activity of M-AG in vivo. The results showed that AG or M-AG inhibited the VEGF secretion of tumor cells, the relative inhibition rates of AG and M-AG being 27.2% and 53.2% respectively at a concentration of $20{\mu}L/mL$. AG and M-AG inhibited the vascular endothelial (VE) cell proliferation with IC50 values of $11.5{\pm}0.5{\mu}L/mL$ and $12.9{\pm}0.4{\mu}L/mL$ respectively. The VE cell migration potential was inhibited significantly (p<0.01) by the AG (${\geq}24{\mu}L/mL$) or M-AG (${\geq}12\mu}L/mL$) treatment. In vivo, neovascularization of CAM treated with M-AG was inhibited significantly (p<0.05) at a concentration of ${\geq}0.4{\mu}L/mL$. This study provided evidence that anti-angiogenesis is one of the anti-tumor mechanisms of AG and M-AG, with the latter as a promising active component.

Flow separation control of two kinds of microvortex generators for a supersonic spinning projectile

Jie Ma,Zhen-gui Huang,Zhihua Chen,Da-wen Xue,Jun-li Han 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.1

Previous studies have shown that Microvortex generators (MVGs) can effectively control the flow separation of supersonic boundary layer. To improve the flight stability of a spinning projectile, two kinds of MVGs, micro ramps and vanes, are applied to control the flow separation of an original standard 155 mm projectile, respectively. Numerical simulations were performed with the use of Detached eddy simulation (DES) method, and the flow fields of the projectile with and without micro MVGs were simulated, the characteristics of the boundary layer and aerodynamic data of three cases were compared and discussed. The numerical results reveal that the effect of the MVGs control is obvious, but their mechanisms are different, and the vanes are more effective than the ramp in the boundary layer control. However, they can both improve the lift and pitching moment of the projectile, and eliminate their oscillations; as a result, its flight stability and firing dispersion can be enhanced. Our results can provide important guidance for improving the flight quality of supersonic projectiles.

Supplementation of guanidinoacetic acid and rumen-protected methionine increased growth performance and meat quality of Tan lambs

Zhang Jian Hao,Li Hai Hai,Zhang Gui Jie,Zhang Ying Hui,Liu Bo,Huang Shuai,Guyader Jessie,Zhong Rong Zhen 아세아·태평양축산학회 2022 Animal Bioscience Vol.35 No.10

Objective: Tan lambs (n = 36, 3 mo old, 19.1±0.53 kg) were used to assess effects of dietary guanidinoacetic acid (GAA) and rumen-protected methionine (RPM) on growth performance, carcass traits, meat quality, and serum parameters. Methods: Lambs were randomly assigned to three treatment groups, with 6 pens per group and 2 lambs per pen. Dietary treatments were: basal diet alone (I); basal diet supplemented with 0.08% GAA+0.06% RPM (II); and basal diet supplemented with 0.08% GAA+0.08% RPM (III). Diets were provided three times a day for 90 d. Intake per pen was recorded daily and individual lamb body weight (BW) was measured monthly. Carcass traits were measured after slaughter and meat quality at the end of the experiment, blood samples were taken on a subgroup of lambs for analysis of indicators mostly related to protein metabolism. Results: Final BW and average daily gain for the first and second month, and for the entire experiment were greater in Treatment II compared to Treatment I (p<0.05), whereas feed to gain ratio was lower (p<0.05). Treatment II had the optimal dressing percentage and net meat weight proportion, as well as crude protein and intramuscular fat concentrations in muscles. Treatment II improved meat quality, as indicated by the greater water holding capacity, pH after 45 min and 48 h, and lower shear force and cooking loss. Dietary supplementation of GAA and RPM also increased the meat color a* and b* values at 24 h. Finally, Treatment II increased total protein, and serum concentrations of albumin and creatinine, but decreased serum urea nitrogen concentrations, indicating improved protein efficiency. Conclusion: In this study, 0.08% GAA+0.06% RPM supplementation improved growth performance and meat quality of Tan lambs. Objective: Tan lambs (n = 36, 3 mo old, 19.1±0.53 kg) were used to assess effects of dietary guanidinoacetic acid (GAA) and rumen-protected methionine (RPM) on growth performance, carcass traits, meat quality, and serum parameters.Methods: Lambs were randomly assigned to three treatment groups, with 6 pens per group and 2 lambs per pen. Dietary treatments were: basal diet alone (I); basal diet supplemented with 0.08% GAA+0.06% RPM (II); and basal diet supplemented with 0.08% GAA+0.08% RPM (III). Diets were provided three times a day for 90 d. Intake per pen was recorded daily and individual lamb body weight (BW) was measured monthly. Carcass traits were measured after slaughter and meat quality at the end of the experiment, blood samples were taken on a subgroup of lambs for analysis of indicators mostly related to protein metabolism.Results: Final BW and average daily gain for the first and second month, and for the entire experiment were greater in Treatment II compared to Treatment I (p<0.05), whereas feed to gain ratio was lower (p<0.05). Treatment II had the optimal dressing percentage and net meat weight proportion, as well as crude protein and intramuscular fat concentrations in muscles. Treatment II improved meat quality, as indicated by the greater water holding capacity, pH after 45 min and 48 h, and lower shear force and cooking loss. Dietary supplementation of GAA and RPM also increased the meat color a* and b* values at 24 h. Finally, Treatment II increased total protein, and serum concentrations of albumin and creatinine, but decreased serum urea nitrogen concentrations, indicating improved protein efficiency.Conclusion: In this study, 0.08% GAA+0.06% RPM supplementation improved growth performance and meat quality of Tan lambs.

Investigations on the influence of control devices to the separation characteristics of a missile from the internal weapons bay

Shiquan Zhu,Zhihua Chen,Hui Zhang,Zhen-gui Huang,Huanhao Zhang 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.5

To ensure the safe separation process of a missile from internal weapons bay, the control device is mounted in front of the internal weapons bay to control the separation process. Based on the coupling of Navier-Stokes (N-S) equations and six-degrees-of-freedom (6DOF) rigid-body motion equations, the separation process of missile under four different conditions (free separation, and rectangle, prism and wedge control) was numerically simulated. The separation process and flow fields were obtained, the aerodynamic parameters and trajectory parameters of four cases compared. Our results show that, the control device can improve the aerodynamic characteristics of the flow field, enhancing the safety of the missile separation. The wedge control device has the best control effect and makes the missile stable, the rectangular and prism control devices have strong bow shock wave and make the pitch angle of the missile large.