Numerical simulations and surrogate-based optimization of cavitation performance for an aviation fuel pump

Xing’an Zhao,Biao Huang,Tairan Chen,Guoyu Wang,Deming Gao,Jing Zhao 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.2

We used computational modeling to investigate the cavitation performance of an aviation fuel pump, and optimize structural parameters using the surrogate-based method. In the numerical simulation, a rotation-curvature correction was adapted to the k-ε turbulence model, and a four-component surrogate fuel was selected to reproduce the physical properties of the China RP-3 kerosene. Then the performance of the aviation fuel pump was predicted. In the optimization, based on the series of the numerical results, Surrogate-based analysis and optimization (SBAO) was used to optimize the structural parameters of the fuel pump (the variation of the outlet blade angle for the inducer △β b1 and the variation of the inlet blade angle for the impeller △β b2 ). The results show that the prediction of cavitation performance agrees well with the experimental data. The results show that cavitation areas are mainly distributed in the inlet of the inducer. The volume of cavities grows with the decreasing NPSHa. The head of the fuel pump has a sudden head-drop when NPSHa ≤ 5.64 m. Furthermore, the surrogate-based approach is available in structural optimization of the fuel pump. The cavitation performance of the optimized pump improved about 22 % with a little drop of head coefficient when △β b1 = 4.33° and △β b2 = 3.24°. The numerical approach employed in this paper can accurately predict the cavitating flow of the high rotating speed fuel pump and the surrogate-based method is available in the structural optimization for a better cavitation performance.

A Novel Molecular Grading Model: Combination of Ki67 and VEGF in Predicting Tumor Recurrence and Progression in Non-invasive Urothelial Bladder Cancer

Chen, Jun-Xing,Deng, Nan,Chen, Xu,Chen, Ling-Wu,Qiu, Shao-Peng,Li, Xiao-Fei,Li, Jia-Ping Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.5

Purpose: To assess efficacy of Ki67 combined with VEGF as a molecular grading model to predict outcomes with non-muscle invasive bladder cancer (NMIBC). Materials: 72 NMIBC patients who underwent transurethral resection (TUR) followed by routine intravesical instillations were retrospectively analyzed in this study. Univariate and multivariate analyses were performed to confirm the prognostic values of the Ki67 labeling index (LI) and VEGF scoring for tumor recurrence and progression. Results: The novel molecular grading model for NMIBC contained three molecular grades including mG1 (Ki67 $LI{\leq}25%$, VEGF $scoring{\leq}8$), mG2 (Ki67 LI>25%, VEGF $scoring{\leq}8$; or Ki67 $LI{\leq}25%$, VEGF scoring > 8), and mG3 (Ki67 LI > 25%, VEGF scoring > 8), which can indicate favorable, intermediate and poor prognosis, respectively. Conclusions: The described novel molecular grading model utilizing Ki67 LI and VEGF scoring is helpful to effectively and accurately predict outcomes and optimize personal therapy.

Oscillation of Cantilever through In-plane Interdigitated Comb-drive Actuators Driving

Xing Chen,Young-Soo Choi,Dong-Weon Lee 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5

We present the concept of scanning force microscopy cantilevers with large deflection and ultra slope at the free end of the lever arm and pure single crystal silicon property exclusion of any types of surface deposition, which are realized through the new actuation mode. This novel cantilever bending actuation mode is firstly proposed totally differing from all of the conventional modes, the out of plane motion of the cantilever is achieved by integrated pre-bent cantilever with in-plane interdigitated comb-drive actuators, the horizontal comb-drive actuator actuation could be transferred to the pre-bent cantilever as a bend moment hence the in-plane actuation of the actuators offer the out of plane actuation for the cantilever.

Ce3+ triggers fenton-like processes in neutral solutions for effective catechol degradation

Xing Chen,Xu Liu,Hai-Bo Wang,Kang-Ping Cui,Rohan Weerasooriya,Shi-Long He,Guang-Hong Li,Jun Pan,Kai Zhou 대한환경공학회 2022 Environmental Engineering Research Vol.27 No.1

Classical Fenton and Fenton-like processes destruct organic pollutants in water non-selectively to complete mineralization. However, the usage of classical Fenton or Fenton-like processes is often limited due to the narrow operational pH window, sludge accumulation, inefficient H₂O₂ and efficiency decline. To overcome these constraints, in this study, we used a homogeneous Fe<SUP>3+</SUP>-Ce<SUP>3+</SUP>-H₂O₂ Fenton-like process to degrade catechol at different experimental conditions. At pH 7, almost 97% of 10 mM catechol can be destructed within 60 min while the degradation by Classical Fenton or Fe<SUP>3+</SUP>-H₂O₂ Fenton-like process only 36.2% and 23.7%. The resultant solution after the degradation contains only traces of cerium ions. The sludge created by the process was extensively characterized by FTIR and XPS spectroscopy to elucidate the fate of cerium ions. Electron spin resonance (ESR) data confirmed •OH as the major free radical in Fe<SUP>3+</SUP>-Ce<SUP>3+</SUP>-H₂O₂ process. Our Fenton-like process widens the optimal pH values to neutral condition.

The carbon nanotube-based nanobiosensor: a key component for ubiquitous real-time bioscreening system?

Chen, Xing,Kim, Daesan,Hong, Seunghun Future Medicine Ltd 2014 Nanomedicine Vol.9 No.5

Nitrogen Addition Changes the Allelopathic Effects of the Root Leachate from the Invasive Weed Stellera chamaejasme L. on a Dominant Grass in the Songnen Grassland

Chen Chen,Fu Xing,Zhuo Li,Ruohui Zhang 한국식물학회 2023 Journal of Plant Biology Vol.66 No.3

Invasive weeds that are poisonous to animals may affect the growth of neighboring palatable plants by releasing allelochemicals in degraded grasslands. Nitrogen (N) input may promote the growth of plants and alter the soil and plant nutrient content and their stoichiometric ratios. However, it is unclear how N addition mediates allelopathic effects of unpalatable weeds on adjacent plants. In this study, a greenhouse experiment was performed to detect the combined effects of root leachate of an invasive and unpalatable weed, Stellera chamaejasme, and N addition on the phenotypic traits and nutrient stoichiometry of a dominant grass, Leymus chinensis, in the Songnen grassland, China. The results showed that leachate addition had no significant effects on traits such as ramet number and biomass but significantly decreased total carbon (C) and the C:N ratio and increased total N in the shoots of L. chinensis. Furthermore, higher N addition changed the original allelopathic effects of the leachate by changing the soil pH, N and phosphorous availability, and microbial activity. This study emphasizes the significance of stoichiometry for detecting plant allelopathy. In particular, N deposition and plant allelopathy should be considered in assessing the relationships between invasive weeds and palatable plants in degraded grasslands.

High resolution regional surface total and diffuse shortwave radiation derived from COMS using artificial neural networks

Xing Chen,Sujong Jeong 한국기상학회 2019 한국기상학회 학술대회 논문집 Vol.2019 No.10

Molecule-based electrorheological material with luminescence property

Chen, Ming-Xing,Liao, Fu-Hui,Shang, Yan-Li,Jia, Yun-Ling,Li, Jun-Ran 한국유변학회 2013 Korea-Australia rheology journal Vol.25 No.1

Molecule-based electrorheological (ER) materials with luminescence property, based on ${\beta}$-cyclodextrin [($C_6O_5H_{10})_7$, ${\beta}$-CD] inclusion compounds between ${\beta}$-CD (host) and the rare earth (RE) (RE=Tb, Eu) complex (guest), have been synthesized as a novel type of ER materials using ${\beta}$-CD, $Tb(NO_3)_3$, $Eu(NO_3)_3$, sulphosalicylic acid ($C_7H_6O_6S{\cdot}2H_2O$, SSA) and m-phthalic acid ($C_8H_6O_4$, MPA) as original materials. The composition, ER performance, luminescence property and dielectric property of the materials have been studied. The results show that the rare earth complex in the cavity of ${\beta}$-CD may enhance the ER performance of ${\beta}$-CD, and the complex (Tb-SSA) of $Tb^{3+}$ can improve more effectively the ER activity of ${\beta}$-CD than that (Eu-MPA) of $Eu^{3+}$ among both of the complexes. The composition and structure are the dominant factors in improving the ER effect. The fluorescence intensity, fluorescence lifetime and emission quantum yield of the particle materials and their suspensions in silicone oil have been tested, and fine luminescence performance has been detected. The material with ER activity and luminescence performance is a novel multifunctional material which would have wide application prospect.

Practical Design Methods for Fire Resistance of Restrained Cellular Steel Beams

Xing Chen,Xiangrong Chen,Gang Li 한국강구조학회 2019 International Journal of Steel Structures Vol.19 No.6

Thermal responses of steel beams under fi re can be intricate, considering the coupling eff ects between material thermalexpansion, mechanical property degradation, and constraints by surrounding structural members. While research eff orts have focused on catenary action of structural members without initial imperfections, few accurate and effi cient methods are found to reveal the fi re resistance of restrained cellular steel beams (RCSBs). In this paper, parametric and regression analysis are applied to investigate the thermal behavior of RCSBs with initial imperfections. Eight groups of RCSBs are set up to demonstrate how various design parameters may aff ect structural responses at elevated temperatures. The results indicate that axial restraint stiff ness ratio, load ratio, and opening diameter-to-height ratio signifi cantly aff ect the structural responses of RCSBs in fi re, followed by the rotational restraint stiff ness ratio and span-to-depth ratio as secondary eff ects. Through the orthogonal and regression analysis, simplifi ed formulas for four characteristic temperatures and four characteristic internal forces are defi ned, which agree with fi nite element results to a certain extent. Meanwhile, reasonable range of each design parameter is put forward for a more effi cient and applicable calculation of thermo-mechanical responses of RCSBs. The proposed formulas are practical, convenient and accurate enough to be applied for engineering design.

A Study of Cold Chain Logistics in China: Hybrid Genetic Algorithm Approach

Xing Chen(진성),Eun-Mi Jang(장은미) 한국산업정보학회 2020 한국산업정보학회논문지 Vol.25 No.6

본 연구에서는 중국에서 유통되고 있는 냉장식품 (-1℃ to 8℃)에 대한 콜드체인 물류(Cold chain logistics: CCL) 모델이 개발되었다. CCL 모델은 분배센터 (Distribution center: DC)와 배포대상지점 (Distribution target points: DT)으로 구성되어 있으며, CCL 모델의 목적함수는 모든 유통업체의 총 유통경로를 최소화하는 것이다. 목적함수를 통한 최적결과 도출을 위해 혼합유전알고리즘(Hybrid genetic algorithm: HGA) 접근법을 제안한다. HGA 접근법은 개선된 K-means 방법과 유전알고리즘을 결합하여 구성된다. 사례연구에서는 유통경로와 유통 가능한 거리 기준으로 CCL 모델에 대해 3개의 시나리오를 고려하였으며, 이를 제안된 HGA접근법을 사용하여 해결하였다. 결과분석을 통해 제안된 HGA접근법을 사용할 경우 유통비용이 절감되고, 마일리지가 약 19%, 20%, 16% 정도 감소됨을 확인하였다. A cold chain logistics (CCL) model for chilled food (-1℃ to 8℃) distributed in China was developed in this study. The CCL model consists of a distribution center (DC) and distribution target points (DT). The objective function of the CCL model is to minimize the total distribution routes of all distributors. To find the optimal result of the objective function, the hybrid genetic algorithm (HGA) approach is proposed. The HGA approach was constructed by combining the improved K-means and genetic algorithm (GA) approaches. In the case study, three scenarios were considered for the CCL model based on the distribution routes and the available distance, and they were solved using the proposed HGA approach. Analysis results showed that the distribution costs and mileage were reduced by approximately 19%, 20% and 16% when the proposed HGA approach was used.