Performance optimization of diesel engine fueled with diesel–jatropha curcas biodiesel blend using response surface methodology

Huaping Xu,Bifeng Yin,Shengji Liu,Hekun Jia 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.8

The present work is aimed at unfolding the effect of fuel supply parameters such as Fuel injection pressure (FIP), Start of injection timing (SOI), Pilot-main injection intervals (PMII) on performance and emission characteristics of 20 % blend of Jatropha curcas biodiesel (J20) under light load operation of a diesel engine. The experiments were designed using design of experiments based on the fractional factorial design of Response surface methodology (RSM). Multiple regression models developed using RSM for measured responses like nitrogen oxides (NO X ), SOOT, hydrocarbon (HC), Brake specific fuel consumption (BSFC) and Brake thermal efficiency (BTE), were found to be statistically significant by Analysis of variance (ANOVA). Interactive effects among FIP, SOI and PMII were analyzed using response surface graphs that were fitted using developed RSM models. Optimization was performed using the desirability approach of the RSM for lesser emissions and BSFC simultaneously with superior BTE. A FIP of 134.11 MPa, SOI of 6.4 BTDC, and PMII of 5.8 CA were found to be optimal values for J20 in the test engine of 21 kW at 1800 rpm. The results of this study show that at optimal input parameters, the values of the NO X , SOOT, HC, BSFC and BTE with a high desirability of 96.7 % are 603.44 ppm, 0.037 FSN, 12.73 ppm, 233.26 g/kW h and 37.31 %, respectively.

High altitude performance optimization of diesel engine fueled with biodiesel-methanol blends using response surface methodology

Huaping Xu,Xinyu Fan 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.9

In the present study, the effects of biodiesel-methanol blends on the performance and emissions of diesel engine at an altitude of 2400 m, were investigated experimentally and using response surface methodology (RSM). The RSM models were developed using experimental data. Methanol ratio, injection pressure (IP) and injection timing (IT) were selected as the input parameters, while power output, brake specific energy consumption (BSEC), nitrogen oxides (NOx) and smoke emissions were chosen as the response parameters. The desirability approach of the RSM was used to optimize the methanol ratio and injection system parameters for improved engine performance and lower emissions at high alitiude. The optimum values of input parameters were 95.27 MPa of IP, 15.13 BTDC of IT and 17.32 % methanol ratio, and the corresponding responses of power output, BSEC, NOx and smoke with a high desirability of 0.767 were 23.7 kW, 9.94 MJ/kWh, 7.08 g/kWh NO X and 0.020 g/kWh, respectively.

Visualization of combustion performance and emission characteristics of a four-cylinder diesel engine at various inlet oxygen concentrations at part loads

Huaping Xu,Shengji Liu,Bifeng Yin,Hekun Jia,Shenghao Yu 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.6

Although exhaust gas recirculation (EGR) is a common way to suppress the nitrogen oxide (NO X ) emissions, it also brings some negative impact on soot emissions and the thermal efficiency in internal combustion engines. We investigated the effects of ambient oxygen concentrations on engine performance, combustion characteristics, and emissions using a four-cylinder diesel engine equipped with an endoscopic visualization system. To estimate the flame temperature and soot distribution, we analyzed these images using a postprocessing program. Experimental results showed that the luminosity of flames in the images was degraded comparatively for the reduced oxygen concentration. Flame temperature distribution also showed similar behavior. As the oxygen concentration decreased, area of soot distribution significantly reduced at IMEP = 0.13 MPa, and only a slight decrease at IMEP = 0.3 MPa. But locally high soot concentration regions increased.

Improving the thermoelectric properties of carbon nanotubes through introducing graphene nanosprings

Xiaoyan Xu,Huaping Xiao,Tao Ouyang,Jianxin Zhong 한국물리학회 2020 Current Applied Physics Vol.20 No.1

Carbon nanotube (CNT) is a typical one-dimensional nanomaterial containing sp2 hybridization states. In this paper, we investigate the ballistic thermoelectric performance of CNTs incorporating graphene nanosprings by using non-equilibrium Green's function. The calculations reveal that the thermoelectric figure of merit could be obviously improved by introducing graphene nanosprings, which is about ten times of that of pristine CNTs at 700 K. Such enhancement is mainly attributed to the remarkable suppression of phononic and electronic thermal conductance and improvement of Seebeck coefficient. In addition, compared to the zigzag graphene nanospring, introducing of the armchair case possesses better thermoelectric performance. The results presented in this paper indicate that embedding graphene nanospring is a viable method to optimize the thermoelectric performance of CNTs and could provide useful theoretical guidance for design and fabrication of CNTs-based thermoelectric devices

Melittin induces autophagy to alleviate chronic renal failure in 5/6-nephrectomized rats and angiotensin II-induced damage in podocytes

Zhang Yufan,Xu Huaping,Qiao Hongwei,Zhao Ya,Jiang Minmin 한국영양학회 2024 Nutrition Research and Practice Vol.18 No.2

"BACKGROUND/OBJECTIVES Chronic renal failure (CRF) is a complex pathological condition that lacks a cure. Certain Chinese medicines, such as melittin, a major component in bee venom, have shown efficacy in treating CRF patients. On the other hand, the mechanisms underlying the therapeutic effects of melittin are unclear. MATERIALS/METHODS A 5/6 nephrectomy model (5/6 Nx) of renal failure was established on rats for in vivo assays, and mouse podocyte clone 5 (MPC5) mouse podocyte cells were treated with angiotensin II (AngII) to establish an in vitro podocyte damage model. The 24-h urine protein, serum creatinine, and blood urea nitrogen levels were evaluated after one, 2, and 4 weeks. Hematoxylin and eosin staining, Masson staining, and periodic acid-Schiff staining were used to examine the pathological changes in kidney tissues. A cell counting kit 8 assay was used to assess the cell viability. Reverse transcription polymerase chain reaction and Western blot were used to assess the mRNA and protein levels in the cells, respectively. RESULTS In the rat 5/6 Nx, melittin reduced the 24-h urinary protein excretion and the serum creatinine and blood urea nitrogen levels. Furthermore, the renal pathology was improved in the melittin-treated 5/6 Nx rats. Melittin promoted podocin, nephrin, Beclin 1, and the LC3II/LC3I ratio and inhibited phosphorylated mammalian target of rapamycin (mTOR)/mTOR in 5/6 Nx-induced rats and AngII-induced MPC5 mouse podocyte cells. Moreover, inhibiting autophagy with 3-MA weakened the effects of melittin on podocin, nephrin, and the LC3II/LC3I ratio in podocytes. CONCLUSION Melittin may offer protection against kidney injury, probably by regulating podocyte autophagy. These results provide the theoretical basis for applying melittin in CRF therapy." "BACKGROUND/OBJECTIVES Chronic renal failure (CRF) is a complex pathological condition that lacks a cure. Certain Chinese medicines, such as melittin, a major component in bee venom, have shown efficacy in treating CRF patients. On the other hand, the mechanisms underlying the therapeutic effects of melittin are unclear. MATERIALS/METHODS A 5/6 nephrectomy model (5/6 Nx) of renal failure was established on rats for in vivo assays, and mouse podocyte clone 5 (MPC5) mouse podocyte cells were treated with angiotensin II (AngII) to establish an in vitro podocyte damage model. The 24-h urine protein, serum creatinine, and blood urea nitrogen levels were evaluated after one, 2, and 4 weeks. Hematoxylin and eosin staining, Masson staining, and periodic acid-Schiff staining were used to examine the pathological changes in kidney tissues. A cell counting kit 8 assay was used to assess the cell viability. Reverse transcription polymerase chain reaction and Western blot were used to assess the mRNA and protein levels in the cells, respectively. RESULTS In the rat 5/6 Nx, melittin reduced the 24-h urinary protein excretion and the serum creatinine and blood urea nitrogen levels. Furthermore, the renal pathology was improved in the melittin-treated 5/6 Nx rats. Melittin promoted podocin, nephrin, Beclin 1, and the LC3II/LC3I ratio and inhibited phosphorylated mammalian target of rapamycin (mTOR)/mTOR in 5/6 Nx-induced rats and AngII-induced MPC5 mouse podocyte cells. Moreover, inhibiting autophagy with 3-MA weakened the effects of melittin on podocin, nephrin, and the LC3II/LC3I ratio in podocytes. CONCLUSION Melittin may offer protection against kidney injury, probably by regulating podocyte autophagy. These results provide the theoretical basis for applying melittin in CRF therapy."

Formal Based Operation Strategy Design for Collaborative Shared Teleoperation System

Fengge Wu,Junsuo Zhao,Huaping Liu,Xiaohui Hu,Fanjiang Xu 제어로봇시스템학회 2010 제어로봇시스템학회 국제학술대회 논문집 Vol.2010 No.10

The cooperative shared tele-operation technology is used to overcome the impact of satellite-earth communication delay and non-structural space environment. To get the appropriate collaborative shared teleoperation system operation sequence, the formal based operation strategy is proposed. Firstly, the task sequence algorithm is introduced. In the algorithm, GSPN (generalize stochastic Petri net) based task sequence models for teleoperation task are established and evaluated to work out the optimal task sequence. And the task sequence is turned into a working mode sequence. Then the working mode transform algorithm is designed in order to reach a fast and stable transform. Based on directed graph theory, the working mode topology graph is obtained. The optimal working mode transform steps can be derived by shortest path algorithm. Finally, unit replacement task is proposed as example to illustrate the operation strategy. The result in this paper can be used in cooperative shared teleoperation system design and on-orbit system task design. It also can be the auxiliary method for teleoperation operator.

Fast-response thermo-sensitive actuator based on asymmetric structured PNIPAM hydrogel with inorganic particles embedding

Fan Zhuanzhuan,Weizhong Xu,Ruofei Wang,Huaping Wu,Aiping Liu 한국고분자학회 2023 Macromolecular Research Vol.31 No.6

Hydrogel actuators have potential applications in many fields because of their multiple responsiveness to environmental stimuli. However, it is still very challenging to design a hydrogel actuator with simple preparation, fast response, and good mechanical properties. In this work, a facile and convenient method to obtain a fast responsive hydrogel actuator has been successfully developed by embedding uniform inorganic particles into Poly(N-isopropylacrylamide) hydrogel network to form an asymmetric structure. By controlling the types and contents of inorganic particles, a wide range of adjustable actuation property can be achieved. At the same time, the introduction of inorganic particles greatly increases the mechanical properties of hydrogels, which is also very important for actuation performance improvement of hydrogel actuators. The optimized hydrogel exhibits relatively fast bending deformation under thermal stimulation (60 ℃), with a bending velocity of about 13.0° s−1 within first 10 s and a bending amplitude of about 328.1° within 1 min. The hydrogel can be designed to be temperature-controlled claw actuators with programmable shapes, indicating its application prospects in encapsulating, grasping, and transporting objects in water environment.

Rapamycin Inhibits Transforming Growth Factor β1-Induced Fibrogenesis in Primary Human Lung Fibroblasts

Yu Gao,Xuefeng Xu,Yan Liang,Dianhua Jiang,Huaping Dai 연세대학교의과대학 2013 Yonsei medical journal Vol.54 No.2

Purpose: The present study was designed to determine whether rapamycin could inhibit transforming growth factor β1 (TGF-β1)-induced fibrogenesis in primary lung fibroblasts, and whether the effect of inhibition would occur through the mammalian target of rapamycin (mTOR) and its downstream p70S6K pathway. Materials and Methods: Primary normal human lung fibroblasts were obtained from histological normal lung tissue of 3 patients with primary spontaneous pneumothorax. Growth arrested, synchronized fibroblasts were treated with TGF-β1 (10 ng/mL) and different concentrations of rapamycin (0.01, 0.1, 1, 10 ng/mL) for 24 h. We assessed m-TOR, p-mTOR, S6K1, p-S6K1 by Western blot analysis, detected type III collagen and fibronectin secreting by ELISA assay, and determined type III collagen and fibronectin mRNA levels by real-time PCR assay. Results: Rapamycin significantly reduced TGF-β1-induced type III collagen and fibronectin levels, as well as type III collagen and fibronectin mRNA levels. Furthermore, we also found that TGF-β1-induced mTOR and p70S6K phosphorylation were significantly down-regulated by rapamycin. The mTOR/p70S6K pathway was activated through the TGF-β1-mediated fibrogenic response in primary human lung fibroblasts. Conclusion: These results indicate that rapamycin effectively suppresses TGF-β1-induced type III collagen and fibronectin levels in primary human lung fibroblasts partly through the mTOR/p70S6K pathway. Rapamycin has a potential value in the treatment of pulmonary fibrosis.