• Title/Summary/Keyword: Regenerative system

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Exergy Analysis of Regenerative Steam-Injection Gas Turbine Systems (증기분사 재생 가스터빈 시스템의 엑서지 해석)

  • Kim, Kyoung-Hoon;Jung, Young-Guan;Han, Chul-Ho
    • Journal of the Korean Society of Propulsion Engineers
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    • v.13 no.4
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    • pp.45-54
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    • 2009
  • An exergy analysis is carried out for the regenerative steam-injection gas turbine systems which has a potential of enhanced thermal efficiency and specific power. Using the analysis model in the view of the second law of thermodynamics, the effects of pressure ratio, steam injection ratio, ambient temperature and turbine inlet temperature are investigated on the performance of the system such as exergetic efficiency, heat recovery ratio of heat exchangers, exergy destruction, loss ratios, and on the optimal conditions for maximum exergy efficiency. The results of computation show that the regenerative steam-injection gas turbine system can make a notable enhancement of exergy efficiency and reduce irreversibilities of the system.

3D Printing Technology and Its Application on Tissue Engineering and Regenerative Medicine (3D 프린팅 기술의 조직공학 및 재생의학 분야 응용)

  • Lee, Junhee;Park, Sua;Kim, Wan Doo
    • Transactions of the KSME C: Technology and Education
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    • v.1 no.1
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    • pp.21-26
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    • 2013
  • In this paper, we introduced various 3D printing technology and it's application on tissue engineering and regenerative medicine. Using the 3D printing technology, Korea Institute of Machinery and Materials (KIMM) has developed 3D bio-printing system. Various 3D tissue engineered scaffolds have been fabricated by the 3D bio-printing system. Cell printing system has been also developed and it is the fundamental technology for organ regeneration in tissue engineering and regenerative medicine.

A Study on the Efficiency of Energy Storage System Applied to the Power Traction System of DC Electric Railway (직류전기철도에서 운행시격에 따른 에너지저장장치의 효율에 관한 연구)

  • Kim, Sung-Dae;Choi, Kyu-Hyoung
    • Proceedings of the KSR Conference
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    • 2011.10a
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    • pp.754-760
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    • 2011
  • In the DC traction system, a large load current of electric railcar leads to a voltage drop when a vehicle starts, and the regenerative power generated by brake system increases the catenary voltage. To minimize the voltage fluctuation during the train operation and make use of the regenerative power, several types of energy storage systems are being studied. The energy storage system that is being recently introduced consists of the supercapacitors for energy storage and the bi-direction DC/DC converter for charge/discharge control. The efficiency of the energy storage system depends on the train operation pattern. In this paper, the operation efficiency of the energy storage system was quantitatively analyzed via simulation study taking consideration of the train operation patterns. The simulation was conducted changing the headway of trains with the energy storage system that uses the bi-direction DC/DC converter and supercapacitor. The simulation results showed that the operation efficiency of the energy storage system increases as the headway increase.

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Islet function within a multilayer microcapsule and efficacy of angiogenic protein delivery in an omentum pouch graft

  • McQuilling, J.P.;Pareta, R.;Sivanandane, S.;Khanna, O.;Jiang, B.;Brey, E.M.;Orlando, G.;Farney, A.C.;Opara, E.C.
    • Biomaterials and Biomechanics in Bioengineering
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    • v.1 no.1
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    • pp.27-39
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    • 2014
  • We have previously described a new multilayer alginate microcapsule system, and the goals of the present study were to assess the in vitro function of islets encapsulated in its inner layer, and the angiogenic ability of FGF-1 delivered from the external layer in an omentum pouch. Following isolation and culture, islets were encapsulated in the inner core of microspheres ($500-600{\mu}m$ in diameter) with a semi-permeable poly-L-ornithine (PLO) membrane separating two alginate layers, and both unencapsulated and encapsulated islet function was assessed by a dynamic glucose perifusion. For angiogenesis experiments, one group of microcapsules without FGF-1 (control) and another (test) containing FGF-1 with heparin encapsulated in the external layer were made. One hundred microcapsules of each group were transplanted in Lewis rats (n = 5/group) and were retrieved after 14 days for assessment of angiogenesis. Glucose perifusion of unencapsulated and encapsulated islets resulted in similar stimulation indices. The release of FGF-1 resulted in increased vascular density compared to controls. In conclusion, islets encapsulated in the core of multilayer alginate microcapsules maintain functionality and the microcapsule's external layer is effective in delivery of FGF-1 to enhance graft neovascularization in a retrievable omentum pouch.

The use of pituitary adenylate cyclase-activating polypeptide in the pre-maturation system improves in vitro developmental competence from small follicles of porcine oocytes

  • Park, Kyu-Mi;Kim, Kyu-Jun;Jin, Minghui;Han, Yongquan;So, Kyoung-Ha;Hyun, Sang-Hwan
    • Asian-Australasian Journal of Animal Sciences
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    • v.32 no.12
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    • pp.1844-1853
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    • 2019
  • Objective: We investigated how pituitary adenylate cyclase-activating polypeptide (PACAP) affects embryonic development during pre-in vitro maturation (pre-IVM) using porcine oocytes isolated from small follicles. Methods: We divided the follicles into the experimental groups by size (SF, small follicles; MF, medium follicles) and treated with and without PACAP and cultured for 18 hours (PreSF[-]PACAP; without PACAP, Pre-SF[+]PACAP; with PACAP) before undergoing IVM. The gene expression related to extracellular matrix formation (amphiregulin, epiregulin, and hyaluronan synthase 2 [HAS2]) and apoptosis (Bcl-2-associated X [BAX], B-cell lymphoma 2, and cysteine-aspartic acid protease 3) was investigated after maturation. The impact on developmental competence was assessed by the cleavage and blastocyst rate and total cell number of blastocysts in embryos generated from parthenogenesis (PA) and in vitro fertilization (IVF). Results: Cleavage rates in the Pre-SF(+)PACAP after PA were significantly higher than SF and Pre-SF(-)PACAP (p<0.05). The cleavage rates between MF and Pre- SF(+)PACAP groups yielded no notable differences after IVF. Pre-SF(+)PACAP displayed the higher rate of blastocyst formation and greater total cell number than SF and Pre-SF(-)PACAP (p<0.05). Cumulus cells showed significant upregulation of HAS2 mRNA in the Pre-SF(+)PACAP compared to the SF (p<0.05). In comparison to other groups, the Pre-SF(+)PACAP group displayed a downregulation in mRNA expression of BAX in matured oocytes (p<0.05). Conclusion: The PACAP treatment during pre-IVM improved the developmental potential of porcine oocytes derived from SF by regulating cumulus expansion and apoptosis of oocytes.

Preparation and Characterization of Genetically Engineered Mesenchymal Stem Cell Aggregates for Regenerative Medicine

  • Kim, Sun-Hwa;Moon, Hyung-Ho;Chung, Bong-Genn;Choi, Dong-Hoon
    • Journal of Pharmaceutical Investigation
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    • v.40 no.6
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    • pp.333-337
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    • 2010
  • Combining cell- and gene-based therapy is a promising therapeutic strategy in regenerative medicine. The aim of this study was to develop genetically modified mesenchymal stem cell (MSC) aggregates using a poly(ethylene glycol) (PEG) hydrogel micro-well array technique. Stable PEG hydrogel micro-well arrays with diameters of 200 to $500\;{\mu}m$ were fabricated and used to generate genetically engineered MSC aggregates. Rat bone marrow-derived MSCs were transfected with a green fluorescent protein (GFP) plasmid as a reporter gene, and aggregated by culturing in the PEG hydrogel micro-well arrays. The resultant cell aggregates had a mean diameter of less than $200\;{\mu}m$, and maintained the mesenchymal phenotype even after genetic modification and cell aggregation. Transplantation of MSC aggregates that are genetically modified to express therapeutic or cell-survival genes may be a potential therapeutic approach for regenerative medicine.

Performance Characteristics Analysis of Combined Cycle Using Regenerative Organic Rankine Cycle and LNG Cold Energy (LNG 냉열과 재생 유기 랭킨 사이클을 이용한 복합 사이클의 성능 특성 해석)

  • KIM, KYOUNG HOON;JUNG, YOUNG GUAN;HAN, CHUL HO
    • Journal of Hydrogen and New Energy
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    • v.31 no.2
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    • pp.234-241
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    • 2020
  • This paper presents a thermodynamic performance analysis of a combined cycle consisting of regenerative organic Rankine cycle (ORC) and liquefied natural gas (LNG) Rankine cycle to recover low-grade heat source and the cold energy of LNG. The mathematical models are developed and the system performances are analyzed in the aspect of thermodynamics. The effects of the turbine inlet pressure and the working fluid on the system performance such as the mass flow rates, heat transfers at heat exchangers, power productions at turbines, and thermal efficiency are systematically investigated. The results show that the thermodynamic performance of ORC such as net power production and thermal efficiency can be significantly improved by the regenerative ORC and the LNG cold energy.

Design and Assessments of a Closed-loop Hydraulic Energy-Regenerative System (폐루프 유압 에너지 회생 시스템에 관한 연구)

  • Hung, H.T.;Yoon, J.I.;Ahn, K.K.
    • 유공압시스템학회:학술대회논문집
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    • 2010.06a
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    • pp.116-125
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    • 2010
  • In this study, a novel hydraulic energy-regenerative system was presented from its proposal through its modeling to its control. The system was based on a closed-loop hydrostatic transmission and used a hydraulic accumulator as the energy storage system in a novel configuration to recover the kinetic energy without any reversion of the fluid flow. The displacement variation in the secondary unit was reduced, which widened the uses of several types of hydraulic pump/motors for the secondary unit. The proposed system was modeled based on its physical attributes. Simulation and experiments were performed to evaluate the validity of the employed mathematical model and the energy recovery potential of the system. The experimental results indicated that the round trip recovery efficiency varied from 22% to 59% for the test bench.

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Study for Charge-Discharge Auto Level-Tuning Algorithm of Energy storage system (에너지저장시스템의 충, 방전 Auto Level-Tuning 알고리즘에 관한 연구)

  • Baek, Seoung-Gil;Lim, Ji-Young;Cha, Joon-Il;Kim, Kil-Dong;Kwon, Kyoung-Min
    • Proceedings of the KSR Conference
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    • 2010.06a
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    • pp.514-520
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    • 2010
  • This paper is about control algorithms that bi-direction DC-DC Converter using Super Capacitor and regenerative power from DC feeding system in train. In order to take advantage of regenerative energy efficient, charge and discharge level value of energy storage system serve as an important factor. Respect to output fluctuations of the substation and catenary voltage changing, we offers Charge-Discharge Auto Level Tuning Algorithms to improve system following of Energy Storage System.

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Evaluation on the Regenerative Cooling Characteristics in Liquid Rocket Engine of 10tf-thrust using Kerosene and Liquid Oxygen as a Propellant (케로신과 액체산소를 추진제로 하는 10톤급 액체로켓엔진의 재생냉각 특성 평가)

  • Han, Poong-Gyoo;Cho, Won-Kook;Cho, Yong-Ho
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.32 no.4
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    • pp.111-117
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    • 2004
  • An analytical study was carried out to evaluate the regenerative cooling characteristics in the liquid rocket engine of a 10tf-thrust level using kerosene as a fuel. As a supplementary cooling method, a radiative cooling was applied to the nozzle extension. It was found out from this work that the cooling system with the regenerative and radiation cooling only is not adaptable for the liquid rocket engine of a 10tf-thrust level using kerosene as a fuel for the $2^{nd}$ stage of the space launch vehicle, with the viewpoint of the thermal and thermo-structural instability and the excessive pressure drop in the cooling channel.