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.

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.

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.

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.

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.

A vision-based system for long-distance remote monitoring of dynamic displacement: experimental verification on a supertall structure

Yi-Qing Ni,You-Wu Wang,Wei-Yang Liao,Wei-Huan Chen 국제구조공학회 2019 Smart Structures and Systems, An International Jou Vol.24 No.6

Dynamic displacement response of civil structures is an important index for in-construction and in-service structural condition assessment. However, accurately measuring the displacement of large-scale civil structures such as high-rise buildings still remains as a challenging task. In order to cope with this problem, a vision-based system with the use of industrial digital camera and image processing has been developed for long-distance, remote, and real-time monitoring of dynamic displacement of supertall structures. Instead of acquiring image signals, the proposed system traces only the coordinates of the target points, therefore enabling real-time monitoring and display of displacement responses in a relatively high sampling rate. This study addresses the in-situ experimental verification of the developed vision-based system on the Canton Tower of 600 m high. To facilitate the verification, a GPS system is used to calibrate/verify the structural displacement responses measured by the vision-based system. Meanwhile, an accelerometer deployed in the vicinity of the target point also provides frequency-domain information for comparison. Special attention has been given on understanding the influence of the surrounding light on the monitoring results. For this purpose, the experimental tests are conducted in daytime and nighttime through placing the vision-based system outside the tower (in a brilliant environment) and inside the tower (in a dark environment), respectively. The results indicate that the displacement response time histories monitored by the vision-based system not only match well with those acquired by the GPS receiver, but also have higher fidelity and are less noise-corrupted. In addition, the low-order modal frequencies of the building identified with use of the data obtained from the vision-based system are all in good agreement with those obtained from the accelerometer, the GPS receiver and an elaborate finite element model. Especially, the vision-based system placed at the bottom of the enclosed elevator shaft offers better monitoring data compared with the system placed outside the tower. Based on a wavelet filtering technique, the displacement response time histories obtained by the vision-based system are easily decomposed into two parts: a quasi-static ingredient primarily resulting from temperature variation and a dynamic component mainly caused by fluctuating wind load.

Asperphenins A and B, Lipopeptidyl Benzophenones from a Marine-Derived <i>Aspergillus</i> sp. Fungus

Liao, Lijuan,Bae, Song Yi,Won, Tae Hyung,You, Minjung,Kim, Seong-Hwan,Oh, Dong-Chan,Lee, Sang Kook,Oh, Ki-Bong,Shin, Jongheon THE AMERICAN CHEMICAL SOCIETY 2017 ORGANIC LETTERS Vol.19 No.8

<P>Asperphenins A (1) and B (2), novel diastereomeric lipopeptidyl benzophenone metabolites, were isolated from a marine-derived Aspergillus sp. fungus. On the basis of the results of combined spectroscopic analyses, the structures of these compounds were determined to be linear assemblies of three motifs: a hydroxy fatty acid, a tripeptide, and a trihydroxybenzophenone. The absolute configurations were assigned using chemical modifications and electronic circular dichroism (ECD) calculations. The novel compounds exhibited significant cytotoxicity on diverse cancer cells.</P>

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.