Numerical simulation and experimental study of quasi-periodic large-scale vortex structures in rod bundle lattices

Yi Liao,Songyang Ma,Hongguang Xiao,Wenzhen Chen,Kehan Ouyang,Zehua Guo,Lele Song Korean Nuclear Society 2024 Nuclear Engineering and Technology Vol.56 No.2

Study of flow behavior within rod bundles has been an active topic. Surface modification technologies are important parts of the design of the fourth generation reactor, which can increase the strength of the secondary flow within the rod bundle lattices. Quasi-periodic large-scale vortex structure (QLVS) is introduced by arranging micro ribs on the surface of rod bundles, which enhanced the scale of the secondary flow between the rod bundle lattices. Using computational fluid dynamics (CFD) and water experiments, the flow field distribution and drag coefficient of the rod-bundle lattices are studied. The secondary flow between the micro-ribbed rod-bundle lattice is significantly enhanced compared to the standard rod-bundle lattice. The numerical simulation results agree well with the experimental results.

An Adaptive Learning System based on Cloud Computing : Implementation and Evaluation of BDS

Yi Liao,Lei Huang,Hang Zhou,Bo Li 보안공학연구지원센터 2016 International Journal of Grid and Distributed Comp Vol.9 No.8

In this paper, we report the design and implementation of an adaptive individualized e-learning environment based on cloud computing named BDS (Beijing Digital School). With its five-layer architecture and its use of cloud computing technology, BDS possesses the characteristics of both a massive access system and an adaptive e-learning environment. This paper focuses on investigating three distributed solutions proposed for load balancing: an active clustering algorithm, a random algorithm and a honey bee foraging algorithm. An experiment comparing 2 groups of students was conducted to evaluate the impact of the proposed environment on learning performance, and the results were analyzed to determine the most effective strategy.

First record of the mulberry psyllid Anomoneura mori Schwarz (Hemiptera: Psylloidea: Psyllidae) from Taiwan

Yi-Chang Liao,Man-Miao Yang 한국응용곤충학회 2018 Journal of Asia-Pacific Entomology Vol.21 No.2

The mulberry psyllid Anomoneura mori Schwarz is reported for the first time from Taiwan. This species is associated with the mulberry tree and is a pest of sericulture. Adults and larvae are described and illustrated for identification. The topic of invasive species is further discussed.

Development of Drying Uniformity for Round Hay Bales Dryer

( Yi-cheng Liao ),( Li-cheng Hsieh ) 한국농업기계학회 2018 한국농업기계학회 학술발표논문집 Vol.23 No.1

In Taiwan, most of the farmer dry hay by natural seasoning. Recent data have shown that moisture content should be 18 % or less in round hay bales for safe storage. If moisture content is too high, the hay will be putrefaction. However, it’s hard for the farmer to harvest on time due to raining season in Taiwan and it would drop hay quality as well. Therefore, it’s important to develop a hay dryer to improve the hay quality. The objective of this research was to modify the round bale hay dryer which had been developed by the Department of Bio-Industrial Mechatronics Engineering of National Chung Hsing University, Taiwan. The moisture content of the round bale could be dried below 18 % by the prototype but its drying efficiency is not sufficient, only 5.6 kg/hr. Therefore, the hay bale was sealed using a heavy fabric to prevent the drying air leaking. The drying-finished hay bales were sampled on three parts, upper, medium and lower layers, respectively. The results show that the innovative device can increase the drying efficiency up to 13.2 kg/hr. For the drying uniformity, the moisture content on the external and internal parts of upper and medium layers were significantly different from central parts’, without sealing. Its standard deviation is 8.02. With sealing, the whole hay bales’ moisture content could reach the goal for storage, and its standard deviation is 1.39. The results show that the new sealing approach can increase the drying uniformity significantly. However, sealing a bale manually takes 10 minutes with two workers. It’s time-consuming. Thus, one mechanism for sealing was designed, and one person could finish the sealing work in a minute.

Study on three-dimensional numerical simulation of shell and tube heat exchanger of the surface ship under marine conditions

Liao Yi,Cai Qi,He Shaopeng,Wang Mingjun,Xiao Hongguang,Gong Zili,Wang Cong,Jia Zhen,Feng Tangtao,Qiu Suizheng 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.4

Shell-and-tube heat exchanger (STHX) is widely used by virtue of its simple structure and high reliability, especially in a space-constrained surface ship. For the STHX of the surface ship, roll, pitch and other motion of the ship will affect the heat transfer performance, resistance characteristics and structural strength of the heat exchanger. Therefore, it is urgent to carry out numerical simulation research on three-dimensional thermal hydraulic characteristics of surface ship STHX under the marine conditions. In this paper, the numerical simulation of marine shell and tube heat exchanger of surface ship was carried out using the porous media model. Firstly, the mathematical physical model and numerical method are validated based on the experimental data of a marine engine cooling water shell and tube heat exchanger. The simulation results are in good agreement with the experimental results. The prediction errors of pressure drop and heat transfer are less than 10% and 1% respectively. The effect of marine conditions on the heat transfer characteristics of the heat exchanger is investigated by introducing the additional force model of marine condition to evaluate the effect of different motion parameters on the heat transfer performance of the heat exchanger. This study could provide a reference for the optimization of marine heat exchanger design.

Newly-Constructed Single-Phase Multistring Multilevel Inverter for Fuel-Cell Microgrid

Yi-Hung Liao,Ching-Ming Lai 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

The objective of this paper is to construct a novel transformerless five-level multistring inverter topology for fuel-cell microgrid system. In this study, a high step-up converter is introduced as a front-end stage to improve the conversion efficiency of conventional boost converters and to stabilize the output DC voltage of various DERs such as PV and fuel cell modules for use with the simplified multilevel inverter. The simplified multilevel inverter requires only six active switches instead of the eight required in the conventional H-bridge cascaded multilevel inverter. In addition, two active switches are operated under line frequency. The presented multistring inverter offers strong advantages such as improved output waveforms, smaller filter size, and lower EMI and THD. Experimental results show the effectiveness of the proposed solution.

CHARACTERIZING THE TIME-FREQUENCY PROPERTIES OF THE 4 Hz QUASI-PERIODIC OSCILLATION AROUND THE BLACK HOLE X-ray BINARY XTE J1550-564

SU, YI-HAO,CHOU, YI,HU, CHIN-PING,YANG, TING-CHANG,HSIEH, HUNG-EN,CHUANG, PO-SHENG,LIN, CHING-PING,LIAO, NAI-HUI The Korean Astronomical Society 2015 天文學論叢 Vol.30 No.2

We present the results from analysis of the Hilbert-Huang transform (HHT) for the 4 Hz quasi-periodic oscillations (QPO) around the black hole X-ray binary XTE J1550-564. The resultant Hilbert spectra demonstrate that the QPO is composed of a series of intermittent signals appearing occasionally. From the analysis of the HHT, we further found the distribution of the lifetimes for the intermittent oscillations and the distribution for the time intervals with no significant signal (the break time). The mean lifetime is 1.45 s and 90% of the oscillation segments have lifetimes less than 3.1 s whereas the mean break time is 0.42 s and 90% of break times are less than 0.73 s. We conclude that the intermittent feature of the QPO could be explained by the Lense-Thirring precession model and rules out interpretations of continual frequency modulation.

Feline mammary carcinoma-derived extracellular vesicle promotes liver metastasis via sphingosine kinase-1-mediated premetastatic niche formation

Yi-Chih Chang,Hao-Ping Liu,Hsiao-Li Chuang,Jiunn-Wang Liao,Pei-Ling Kao,Hsun-Lung Chan,Ter-Hsin Chen,Yu-Chih Wang 한국실험동물학회 2023 Laboratory Animal Research Vol.39 No.4

Background: Feline mammary carcinoma (FMC) is one of the most prevalent malignancies of female cats. FMC is highly metastatic and thus leads to poor disease outcomes. Among all metastases, liver metastasis occurs in about 25% of FMC patients. However, the mechanism underlying hepatic metastasis of FMC remains largely uncharacterized. Results: Herein, we demonstrate that FMC-derived extracellular vesicles (FMC-EVs) promotes the liver metastasis of FMC by activating hepatic stellate cells (HSCs) to prime a hepatic premetastatic niche (PMN). Moreover, we provide evidence that sphingosine kinase 1 (SK1) delivered by FMC-EV was pivotal for the activation of HSC and the formation of hepatic PMN. Depletion of SK1 impaired cargo sorting in FMC-EV and the EV-potentiated HSC activation, and abolished hepatic colonization of FMC cells. Conclusions: Taken together, our findings uncover a previously uncharacterized mechanism underlying liver-metastasis of FMC and provide new insights into prognosis and treatment of this feline malignancy.

Oxygen-loaded microbubble-mediated sonoperfusion and oxygenation for neuroprotection after ischemic stroke reperfusion

Yi‑Ju Ho,Hsiang‑Lung Cheng,Lun‑De Liao,Yu‑Chun Lin,Hong‑Chieh Tsai,Chih‑Kuang Yeh 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Background Ischemic stroke-reperfusion (S/R) injury is a crucial issue in the protection of brain function after thrombolysis. The vasodilation induced by ultrasound (US)-stimulated microbubble cavitation has been applied to reduce S/R injury through sonoperfusion. The present study uses oxygen-loaded microbubbles (OMBs) with US stimulation to provide sonoperfusion and local oxygen therapy for the reduction of brain infarct size and neuroprotection after S/R. Methods The murine S/R model was established by photodynamic thrombosis and thrombolysis at the remote branch of the anterior cerebral artery. In vivo blood flow, partial oxygen pressure ( pO2), and brain infarct staining were examined to analyze the validity of the animal model and OMB treatment results. The animal behaviors and measurement of the brain infarct area were used to evaluate long-term recovery of brain function. Results The percentage of blood flow was 45 ± 3%, 70 ± 3%, and 86 ± 2% after 60 min stroke, 20 min reperfusion, and 10 min OMB treatment, respectively, demonstrating sonoperfusion, and the corresponding pO2 level was 60 ± 1%, 76 ± 2%, and 79 ± 4%, showing reoxygenation. After 14 days of treatment, a 87 ± 3% reduction in brain infarction and recovery of limb coordination were observed in S/R mice. The expression of NF-κB, HIF-1α, IL-1β, and MMP-9 was inhibited and that of eNOS, BDNF, Bcl2, and IL-10 was enhanced, indicating activation of anti-inflammatory and anti-apoptosis responses and neuroprotection. Our study demonstrated that OMB treatment combines the beneficial effects of sonoperfusion and local oxygen therapy to reduce brain infarction and activate neuroprotection to prevent S/R injury.

THE UPDATED ORBITAL EPHEMERIS OF DIPPING LOW MASS X-ray BINARY 4U 1624-49

LIAO, NAI-HUI,CHOU, YI,HSIEH, HUNG-EN,CHUANG, PO-SHENG The Korean Astronomical Society 2015 天文學論叢 Vol.30 No.2

We present our analysis results for an updated orbital ephemeris for the dipping low mass X-ray binary 4U 1624-49, using the light curve collected by the All Sky Monitor (ASM) on board the Rossi X-ray Timing Explorer (RXTE) and the Monitor of All-Sky X-ray Image (MAXI). To make clear dip profiles, the light curve from the ASM and the MAXI were divided into ten 500d segments and four 400d segments for ASM and MAXI light curves, respectively, and folded with the linear ephemeris proposed by Smale et al. (2001). The phases of dip centers were determined by the method adopted from Hu et al. (2008). The phase drift was then fitted with a linear function. We obtained an updated orbital period of 0.869896(1) d and a phase zero epoch of JD 2450088.6618(57). No clear orbital period derivative is detected with a 2-sigma upper limit of $1.4{\times}10^{-6}(yr)^{-1}$ from a quadratic curve fitting of the dip phase evolution.