Novel Roaming and Stationary Tethered Aerial Robots for Continuous Mobile Missions in Nuclear Power Plants

구범우,Su Y. Choi,최영수,Guowei Cai,Lakmal Seneviratne,임춘택 한국원자력학회 2016 Nuclear Engineering and Technology Vol.48 No.4

In this paper, new tethered aerial robots including roaming tethered aerial robots (RTARs)for radioactive material sampling and stationary tethered aerial robots (STARs) for environmentmonitoring are proposed to meet extremely-long-endurance missions of nuclearpower plants. The flight of the proposed tethered aerial robots may last for a few days oreven a few months as long as the tethered cable provides continuous power. A high voltageAC or DC power system was newly adopted to reduce the mass of the tethered cable. TheRTAR uses a tethered cable spooled from the aerial robot and an aerial tension controlsystem. The aerial tension control system provides the appropriate tension to the tetheredcable, which is accordingly laid down on the ground as the RTAR roams. The STAR includesa tethered cable spooled from the ground and a ground tension control system, whichenables the STAR to reach high altitudes. Prototypes of the RTAR and STAR were designedand successfully demonstrated in outdoor environments, where the load power, powertype, operating frequency, and flight attitude of the RTAR and STAR were: 180 W, AC100 kHz, and 20 m; and 300 W, AC or DC 100 kHz, and 80 m, respectively.

Characterization of fermented pomegranate juice: ACE inhibitory activity under in vitro digestion, antioxidant capacity, phenolics composition, chemical properties and sensory evaluation

Lichen Zhang,Linlin Wang,Jingwei Cai,Ting Yang,Jianke Li,Guowei Shu 한국식품과학회 2024 Food Science and Biotechnology Vol.33 No.4

Consuming pomegranate juice (PJ) is beneficial for hypertensive regulation because of the phenolic compounds in PJ and their inhibitory activity on angiotensin-I-converting enzyme (ACE). To better utilize bioactive function of food, microorganism fermentation has been adopted to alter phenolic metabolism. This study confirms that even under in vitro digestion, fermented PJ (FPJ) maintains higher ACE inhibitory activity than that of PJ. The main phenolic compounds in PJ were compared either under fermentation or in vitro digestion. This study finds that fermentation promotes antioxidant capacity of PJ. The chemical properties of FPJ are evaluated and the corresponding relationship with bioactivities is analyzed. A sensory evaluation comparison is conducted between FPJ and PJ, furnishing interesting information for consumers. This study highlights the relationship between ACE inhibitory activity of PJ and phenolic composition under fermentation and in vitro digestion, providing novel insights for diet regulation of phenolic-rich FPJ in ACE inhibition therapy.

Multi-Objective Optimal Scheduling of Distribution Network with Electric Vehicle Charging Load Considering Time-Varying Road Impedance

Huang Nantian,Hu Lei,Wang Rijun,Cai Guowei,Guo Yu,Zhao Xuanyuan 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.4

As the influence of time-varying temperature and driving speed on electric vehicle charging load is not considered in the process of distribution network scheduling, a multiobjective optimal scheduling model for distribution networks, which considers electric vehicle charging load, is proposed. First, considering the time-varying road congestion degree to update the road impedance, an enhanced Dijkstra algorithm is proposed to determine the optimal travel route for EV users. Second, considering the dynamic influence of time-varying temperature and driving speed on EV power consumption, the EV charging load is analysed. Third, the distribution network load, tie line power fluctuation, and dispatching operation cost factors are applied to establish a multiobjective optimal dispatching model for the distribution network, and a multiobjective particle swarm algorithm based on dynamic learning factors is proposed to solve the model. The VIKOR method obtains the scheduling scheme closest to the ideal solution from the solution set. The simulation experiment suggests that the dispatching model in this paper can reduce not only the dispatching operation cost of the distribution network but also the distribution network load and power fluctuation of the tie line.

A Bidirectional Dual Buck-Boost Voltage Balancer with Direct Coupling Based on a Burst-Mode Control Scheme for Low-Voltage Bipolar-Type DC Microgrids

Liu, Chuang,Zhu, Dawei,Zhang, Jia,Liu, Haiyang,Cai, Guowei The Korean Institute of Power Electronics 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.6

DC microgrids are considered as prospective systems because of their easy connection of distributed energy resources (DERs) and electric vehicles (EVs), reduction of conversion loss between dc output sources and loads, lack of reactive power issues, etc. These features make them very suitable for future industrial and commercial buildings' power systems. In addition, the bipolar-type dc system structure is more popular, because it provides two voltage levels for different power converters and loads. To keep voltage balanced in such a dc system, a bidirectional dual buck-boost voltage balancer with direct coupling is introduced based on P-cell and N-cell concepts. This results in greatly enhanced system reliability thanks to no shoot-through problems and lower switching losses with the help of power MOSFETs. In order to increase system efficiency and reliability, a novel burst-mode control strategy is proposed for the dual buck-boost voltage balancer. The basic operating principle, the current relations, and a small-signal model of the voltage balancer are analyzed under the burst-mode control scheme in detail. Finally, simulation experiments are performed and a laboratory unit with a 5kW unbalanced ability is constructed to verify the viability of the bidirectional dual buck-boost voltage balancer under the proposed burst-mode control scheme in low-voltage bipolar-type dc microgrids.

The putative polysaccharide synthase AfCps1 regulates Aspergillus fumigatus morphogenesis and conidia immune response in mouse bone marrow-derived macrophages

Wang Sha,Yuan Anjie,Zeng Liping,Hou Sikai,Wang Meng,Li Lei,Cai Zhendong,Zhong Guowei 한국미생물학회 2021 The journal of microbiology Vol.59 No.1

Aspergillus fumigatus is a well-known opportunistic pathogen that causes invasive aspergillosis (IA) infections with high mortality in immunosuppressed individuals. Morphogenesis, including hyphal growth, conidiation, and cell wall biosynthesis is crucial in A. fumigatus pathogenesis. Based on a previous random insertional mutagenesis library, we identified the putative polysaccharide synthase gene Afcps1 and its paralog Afcps2. Homologs of the cps gene are commonly found in the genomes of most fungal and some bacterial pathogens. Afcps1/cpsA is important in sporulation, cell wall composition, and virulence. However, the precise regulation patterns of cell wall integrity by Afcps1/cpsA and further effects on the immune response are poorly understood. Specifically, our in-depth study revealed that Afcps1 affects cell-wall stability, showing an increased resistance of ΔAfcps1 to the chitinmicrofibril destabilizing compound calcofluor white (CFW) and susceptibility of ΔAfcps1 to the β-(1,3)-glucan synthase inhibitor echinocandin caspofungin (CS). Additionally, deletion of Afcps2 had a normal sporulation phenotype but caused hypersensitivity to Na+ stress, CFW, and Congo red (CR). Specifically, quantitative analysis of cell wall composition using high-performance anion exchange chromatography- pulsed amperometric detector (HPAEC-PAD) analysis revealed that depletion of Afcps1 reduced cell wall glucan and chitin contents, which was consistent with the downregulation of expression of the corresponding biosynthesis genes. Moreover, an elevated immune response stimulated by conidia of the ΔAfcps1 mutant in marrow-derived macrophages (BMMs) during phagocytosis was observed. Thus, our study provided new insights into the function of polysaccharide synthase Cps1, which is necessary for the maintenance of cell wall stability and the adaptation of conidia to the immune response of macrophages in A. fumigatus.

A Bidirectional Dual Buck-Boost Voltage Balancer with Direct Coupling Based on a Burst-Mode Control Scheme for Low-Voltage Bipolar-Type DC Microgrids

Chuang Liu,Dawei Zhu,Jia Zhang,Haiyang Liu,Guowei Cai 전력전자학회 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.6

DC microgrids are considered as prospective systems because of their easy connection of distributed energy resources (DERs) and electric vehicles (EVs), reduction of conversion loss between dc output sources and loads, lack of reactive power issues, etc. These features make them very suitable for future industrial and commercial buildings’ power systems. In addition, the bipolar-type dc system structure is more popular, because it provides two voltage levels for different power converters and loads. To keep voltage balanced in such a dc system, a bidirectional dual buck-boost voltage balancer with direct coupling is introduced based on P-cell and N-cell concepts. This results in greatly enhanced system reliability thanks to no shoot-through problems and lower switching losses with the help of power MOSFETs. In order to increase system efficiency and reliability, a novel burst-mode control strategy is proposed for the dual buck-boost voltage balancer. The basic operating principle, the current relations, and a small-signal model of the voltage balancer are analyzed under the burst-mode control scheme in detail. Finally, simulation experiments are performed and a laboratory unit with a 5kW unbalanced ability is constructed to verify the viability of the bidirectional dual buck-boost voltage balancer under the proposed burst-mode control scheme in low-voltage bipolar-type dc microgrids.