Causal analysis of natural gas station pipelines vibration and reduction measures

Wenwu Yang,Xin Li,Yuhan Tao,Kang Cen,Yunqiao Wen 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.9

The existing studies on the strong vibration problem of the outbound process pipeline of a natural gas transfer station focus on the pipeline process with a compressor. This work proposes a structural innovation to eliminate the pipeline vibration without compressor by experiment and numerical simulation. A simulation model was established based on the physical dimensions. Hammer test and finite element method validated the proposed model for natural gas stations pipelines. It was found that in branch 1 and 2 occur the first two coupled modes. In addition, three kinds of vibration reduction schemes, such as increasing sleeve and increasing pipe diameter, are proposed to increase the pipe rigidity and reduce the excitation force to control the vibration. It is revealed that adding sleeves to the branch pipes 1 and 2 can better suppress pipe vibration by referring to related evaluation standards. This case shows that performing variable-condition vibration testing and spectrum characteristics analysis of pipelines can easily reveal the main vibration sources and provide solutions for pipeline vibration reduction treatment.

Biomimetic apatite formed on cobalt-chromium alloy: A polymer-free carrier for drug eluting stent

Chen, Cen,Yao, Chenxue,Yang, Jingxin,Luo, Dandan,Kong, Xiangdong,Chung, Sung-Min,Lee, In-Seop Elsevier 2017 Colloids and surfaces Biointerfaces Vol.151 No.-

<P><B>Abstract</B></P> <P>In this study, sirolimus (SRL) was loaded within biomimetic apatite formed on cobalt-chromium (Co-Cr) alloy, which has been reported for the first time, to inhibit the in-stent restenosis. Two different groups of loading SRL within biomimetic apatite were prepared: Group A (mono-layer of apatite/SRL) and Group B (bi-layer of apatite/SRL). Group A and Group B showed the biphasic pattern of SRL release up to 40 and 90days, respectively. The attachment of human artery smooth muscle cell (HASMC) for both Group A and Group B was significantly inhibited, and proliferation dramatically decreased with the release of SRL. Noteworthily, biomimetic apatite alone also suppressed the SMC proliferation. The porous biomimetic apatite uniformly covered Co-Cr stent without crack or webbings. After balloon expansion, the integrity of biomimetic apatite was sufficient to resist delamination or destruction. Thus, this study demonstrated that biomimetic apatite is a promising drug carrier for potential use in stents.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Biomimetic apatite is formed on Co-Cr alloy as a polymer-free drug carrier. </LI> <LI> To inhibit in-stent restenosis, sirolimus is loaded within apatite in two ways. </LI> <LI> Porous and biodegradable biomimetic apatite releases of sirolimus over 40days. </LI> <LI> Integrity of biomimetic apatite is sufficient for clamping and balloon expansion. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Analysis and Optimization on U-shaped Damping Groove for Flow Ripple Reduction of Fixed Displacement Axial-Piston Pump

Hao-cen HONG,Bin ZHANG,Min YU,Qi ZHONG,Hua-yong YANG 한국유체기계학회 2020 International journal of fluid machinery and syste Vol.13 No.1

The periodic flow ripples and pressure pulsations in a fixed-displacement axial-piston pump will directly impact its dynamic characteristics. To reduce the discharge flow ripples and pressure pulsations is one of the design challenges. An optimizing method is investigated herein using numerical models. The U-shaped damping groove at the discharge kidney groove is the primary optimized object. The numerical models of a fixed-displacement axial-piston pump with nine pistons are proposed and developed by MATLAB/Simulink. The effects of width radius, groove depth and groove length angle on flow dynamics are discussed. The optimization models based on the root-mean-square, the pulsation and the suction-extrusion ratio are proposed. As results show that the optimized structure can decrease the flow ripples from 31.08% to 20.33%.

Mechanism underlying the effect of conventional drying on the grinding characteristics of Ximeng lignite

Yumeng Yang,Jianzhong Liu,Xiang He,Zhihua Wang,Junhu Zhou,Kefa Cen 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.4

Same amounts of moisture were removed from Ximeng lignite (XL) with different particle size ranges pretreated at different drying temperatures. The effect of conventional drying on the grindability of the XLs was investigated. Increasing the drying temperature improved the grindability of all the samples. The results of scanning electron microscopy and mercury intrusion porosimetry revealed that the dominant mechanism enhancing the grindability of XL with high moisture was the pore structure destruction induced by the steam jet flow generated with the removal of moisture. Especially, the development of large fractures had a strong connection with the change in the grindability. According to the pore size distribution, the internal structure of the 2.5-4.0mm coal samples did not develop well under high drying temperature because of the exceedingly short heating time. Therefore, coal particle size, drying temperature, and heating time must be coordinated well to achieve the enhanced drying effect. The grindability of XL had a negative linear correlation with the pore volume fractal dimension, revealing the possibility of fractal dimension for the analysis of lignite grindability.

A Clustering Algorithm Based on Multi-agent Meta-heuristic Architecture

Zhu Qiang,Shun Yuqiang,Cen Yang 보안공학연구지원센터 2014 International Journal of Hybrid Information Techno Vol.7 No.2

Improving the CO2 fixation rate by increasing flow rate of the flue gas from microalgae in a raceway pond

Jun Cheng,Zongbo Yang,Junhu Zhou,Kefa Cen 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.2

Residence time of flue gas bubbles with different solution velocities and the influence of NOX and SO2 from flue gas on pH values of culture solutions were analyzed based on large-scale raceway reactors. Microalgal growth and CO2 fixation rates were also investigated with different gas flow rates. Bubble residence time was ~1.1 s when the solution velocity was 20 cm/s. The NOX and SO2 effects on microalgal growth were negligible, although 66% NOX and 95% SO2 were captured by the microalgal solution. Microalgal biomass productivity increased from 10.3 to 14.1 g/m2/d when flue gas flow rate increased from 20 to 50m3/h. CO2 fixation and microalgae biomass productivity increased further from 26.3 to 31.9 g/m2/d and from 14.1 to 17.1 g/m2/d, respectively, upon increase of flue gas flow rate from 50 to 150m3/h.

Study on the Gas-liquid Flow Characteristics in the Reversing Bucket of Water Jet Propulsion

Zhongyong Pan,Chunhai Cen,Ping Zong,Fall Ibra,Bo Yang 한국유체기계학회 2020 International journal of fluid machinery and syste Vol.13 No.2

To investigate the gas-liquid two-phase flow characteristics in the reversing bucket of water jet propulsion, the numerical simulations based on the Euler-Euler inhomogeneous model was conducted to the internal flow field of the reversing bucket under 1%~12% different inlet gas volume fractions (α). Based on that, the gas distribution, gas-liquid velocity streamlines and thrust changing were obtained to discuss the gas-liquid flow characteristics and the influence on the thrust of the reversing bucket. The calculation results show that the gas mainly distributes in the inner part of the reversing bucket flow passage under different inlet gas volume fractions. On the condition that the inlet gas volume fraction is more than 2%, the gas accumulation has occurred in the inlet section of the flow passage. With the increasing of inlet gas volume fraction, average velocity and pressure increase gradually at each cross-section of reversing bucket flow passage, and at the higher gas concentration in each cross-section, where the vortex will exist, indicating that the gas concentration has a great relationship with the vortex aggregation in the reversing bucket flow passage. When the inlet gas volume fraction is 7%, the thrust reaches the maximum. It shows that the appropriate gas can effectively improve the thrust efficiency of the reversing bucket.

Elevated TRAF4 expression impaired LPS-induced autophagy in mesenchymal stem cells from ankylosing spondylitis patients

Jinteng Li,Peng Wang,Zhongyu Xie,Rui Yang,Yuxi Li,Xiaohua Wu,Hongjun Su,Wen Deng,Shan Wang,Zhenhua Liu,Shuizhong Cen,Yi Ouyang,Yanfeng Wu,Huiyong Shen 생화학분자생물학회 2017 Experimental and molecular medicine Vol.49 No.-

Ankylosing spondylitis (AS) is a type of autoimmune disease that predominantly affects the spine and sacroiliac joints. However, the pathogenesis of AS remains unclear. Some evidence indicates that infection with bacteria, especially Gram-negative bacteria, may have an important role in the onset and progression of AS. Recently, many studies have demonstrated that mesenchymal stem cells (MSCs) dysfunction may contribute to the pathogenesis of many rheumatic diseases. We previously demonstrated that MSCs from AS patients exhibited markedly enhanced osteogenic differentiation capacity in vitro under non-inflammatory conditions. However, the properties of MSCs from AS patients in an inflammatory environment have never been explored. Lipopolysaccharide (LPS), a proinflammatory substance derived from the outer membrane of Gram-negative bacteria, can alter the status and function of MSCs. However, whether MSCs from AS patients exhibit abnormal responses to LPS stimulation has not been reported. Autophagy is a lysosome-mediated catabolic process that participates in many physiological and pathological processes. The link between autophagy and AS remains largely unknown. The level of autophagy in ASMSCs after LPS stimulation remains to be addressed. In this study, we demonstrated that although the basal level of autophagy did not differ between MSCs from healthy donors (HDMSCs) and ASMSCs, LPS-induced autophagy was weaker in ASMSCs than in HDMSCs. Specifically, increased TRAF4 expression in ASMSCs impaired LPS-induced autophagy, potentially by inhibiting the phosphorylation of Beclin-1. These data may provide further insight into ASMSC dysfunction and the precise mechanism underlying the pathogenesis of AS.

Asymmetric reduction of chloroacetophenones to produce chiral alcohols with microorganisms

Zhimin Ou,Jianping Wu,Lirong Yang,Peilin Cen 한국화학공학회 2008 Korean Journal of Chemical Engineering Vol.25 No.1

Four strains of yeast with reduction activity of chloroacetophenones were screened, in which Saccharomyces cerevisiae B5 showed best reduction activity and stereoselectivity. High optical purity (R)-2'-chloro-1-phenylethanol can be obtained with Saccharomyces cerevisiae B5 as biocatalyst. The influence of several co-substrates on the enantiometric excess (ee%) and yield of (R)-2'-chloro-1-phenylethanol was evaluated. 5% (v/v) ethanol is optimal cosubstrate for (R)-2'-chloro-1-phenylethanol formation. The optimal bioconversion conditions of 2'-chloroacetophenone catalyzed by Saccharomyces cerevisiae B5 are as follows: pH 8.0, 25 oC and 24 h. The yield and the enantiometric excess of (R)-2'-chloro-1-phenylethanol can both reach more than 99% with 10.75 g/l Saccharomyces cerevisiae B5 (the cell dry weight) and 1 g/l 2'-chloroacetophenone used in the biotransformation.

Growth and Differentiation Effects of Homer3 on a Leukemia Cell Line

Li, Zheng,Qiu, Hui-Ying,Jiao, Yang,Cen, Jian-Nong,Fu, Chun-Mei,Hu, Shao-Yan,Zhu, Ming-Qing,Wu, De-Pei,Qi, Xiao-Fei Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.4

The Homer protein family, also known as the family of cytoplasmic scaffolding proteins, which include three subtypes (Homer1, Homer2, Homer3). Homer3 can regulate transcription and play a very important role in the differentiation and development for some tissues (e.g. muscle and nervous systems). The current studies showed that Homer3 abnormal expression changes in acute myeloid leukemia (AML). Forced expression of Homer3 in transfected K562 cells inhibited proliferation, influenced the cell cycle profile, affected apoptosis induced by $As_2O_3$ through inhibition of Bcl2 expression, and also promoted cell differentiation induced by 12-O-tetra decanoylphorbol-acetate (TPA). These results showed that Homer3 is a novel gene which plays a certain role in the occurrence and development of AML.