Realization of a Metalized Gel Fuel Ramjet

Benveniste Natan 한국추진공학회 2010 한국추진공학회 학술대회논문집 Vol.2010 No.11

The high specific impulse of the ramjet engine, combined with the ability of a gel to carry metal particles, make the Gel Fuel Ramjet a most adequate solution for a mid-high range sustainer, The goal of the present study is to verify experimentally the feasibility of such a concept. A test facility and a lab-scale motor have been designed and built to investigate atomization, ignition and firing processes of a gel hydrocarbon fuel, with and without metal additives, as well as to check the ramjet operation as a whole. The present paper presents the experimental system in detail as well as qualitative results of a few firing tests.

The Equivalence of t-wise and Pareto Optimality: A Generalization

Lawrence Benveniste,Byoung Heon Jun 서울대학교 경제연구소 1990 Seoul journal of economics Vol.3 No.3

We study the optimality of allocations obtained in an economy in which agents are not coordinated by a single consistent system like Walrasian auctioneer. In order to exploit all the opportunities for mutually beneficial trade, people must find a way to coordinate themselves beyond the limitation set by the incomplete market structure. We will consider economies whose market structure does not necessarily permit a full coordination, and completely characterize the condition which must be satisfied to guarantee a Pareto optimal outcome. Our result generalizes previous equivalence conditions.

공기가열히터와 모사추진제를 이용한 덕티드 로켓의 연소실험기법

김수종(Soojong Kim),Benveniste Natan 한국추진공학회 2015 한국추진공학회 학술대회논문집 Vol.2015 No.11

덕티드로켓 개발과정에서 검토해야 할 성능, 설계 변수를 도출하는데 유용한 모사 실험장치와 실험기법에 대해 기술하고, 유용성을 검토하였다. 고공 비행환경을 모사하기 위해 직접연결식(directconnect type) 실험장치를 구성하였으며, 실험장치는 연소식 공기가열히터, 연료농후가스를 생성하는 가스발생기, 실험 정밀도와 편의성을 제공하기 위한 모사추진제 공급장치, 직접연결식 공기공급장치, 고압으로 압축 저장된 공기를 블로우 다운(blow down) 방식으로 공급하기 위한 공기압축기와 고압용기로 구성된다. 고안된 실험장치와 실험기법은 덕티드로켓의 농후연소가스와 흡입공기 상호간의 공기-열역학적 특성 분석, 연소실 및 공기흡입구 형상설계에 유용하게 활용될 것으로 판단된다. The experimental methods to determine the design and performance parameters in the development process of a ducted rocket were described, and the availability of experimental setup and methods was examined. Experimental setup of the direct-connect type to simulate the flight conditions of the high speed and high altitude was developed. It is composed of vitiated air heater, gas generator, feeding system of propellant simulant, air feeding system using a direct-connect type, air compressor and high pressure tank to feed by the blow down method. Experimental setup and methods, which are presented in this study, can be effectively used for the analysis of aerothermodynamic characteristics on the interaction between fuel-rich exhaust gas and incoming air, and design of combustor and air inlet shapes.

Cell Surface Expression of Tumor Necrosis Factor-Alpha by Activated Rat Astrocytes

Chung, Il-Yup,Benveniste, Etty N. Korean Society for Biochemistry and Molecular Biol 1996 Journal of biochemistry and molecular biology Vol.29 No.6

Astrocyte are the major glial cell type in the central nervous system (CNS), and analogous to macrophage, mediates the number of immune responses such as production of cytokines including tumor necrosis factor alpha ($TNF-{\alpha}$) upon activation. $TNF-{\alpha}$ has been implicated in neuroimmunological disorders through killing oligodendrocytes and thus causing demyelination. It has been previously demonstrated that mitogen-activated T cells synthesized a 26 kDa precursor form of $TNF-{\alpha}$ which is bound to the surface of a membrane, and is later secreted as a 17 kDa mature version. In order to examine whether astrocytes would produce the transmembrane form of $TNF-{\alpha}$, astrocytes were stimulated with biological stimuli and the membrane form of $TNF-{\alpha}$ was analyzed by Western blot and FACS analysis. When astrocytes are stimulated with lipopolysaccharide (LPS), $IFN-{\gamma}/LPS$, or $IFN-{\gamma}/IL-1{\beta}$, they were able to express a membrane-anchored $TNF-{\alpha}$ of approximately 26 kDa protein which was immunoreactive to an $anti-TNF-{\alpha}$ antibody, whereas unstimulated astrocytes or astrocytes treated with $IFN-{\gamma}$ or $IL-1{\beta}$ alone was not. Our FACS data were also consistent with the immunoblot analysis. Our result suggests that the membrane form of $TNF-{\alpha}$ expressed by activated astrocytes may cause local damage to oligodendrocytes by direct cell-cell contact and contribute to demyelination observed in multiple sclerosis (MS) and experimental allergic encephalomyelitis (EAE).

Cell Surface Expression of Tumor Necrosis Factor - Alpha by Activated Rat Astrocytes

Chung, Il Yup,Benveniste, Etty N 생화학분자생물학회 1982 BMB Reports Vol.29 No.6

Astrocyte are the major glial cell type in the central nervous system (CNS), and analogous to macrophage, mediates the number of immune responses such as production of cytokines including tumor necrosis factor alpha (TNF-a) upon activation. TNF-a has been implicated in neuroimmunological disorders through killing oligodendrocytes and thus causing demyelination. It has been previously demonstrated that mitogen-activated T cells synthesized a 26 kDa precursor form of TNF-α which is bound to the surface of a membrane, and is later secreted as a 17 kDa mature version. In order to examine whether astrocytes would produce the transmembrane form of TNF-α, astrocytes were stimulated with biological stimuli and the membrane form of TNF-α was analyzed by Western blest and FRCS analysis. When astrocytes are stimulated with lipopolysaccharide (LPS), IFN-γ/LPS, or IFN-γ/IL-1β, they were able to express a membraneanchored TNF-α of approximately 26 kDa protein which was immunoreactive to an anti-TNF-α antibody. whereas unstimulated astrocytes or astrocytes treated with IFN-γ or IL-1β alone was not. Our FRCS data were also consistent with the immunoblot analysis. Our result suggests that the membrane form of TNF-α expressed by activated astrucytes may cause local damage to oligodendrocytes by direct cell-cell contact and contribute to demyelination observed in multiple sclerosis (MS) and experimental allergic encephalomyelitis (ERE).

POSTERS / PW-118 : CYTOKINE REGULATION OF CHEMOKINE AND CXCR4 EXPRESSION BY HUMAN ASTROCYTES

(Jae Wook Oh),(Etty N . Benveniste) 한국생화학분자생물학회 (구 한국생화학회) 1999 6th IUBMB SEOUL CONFERENCE Vol.- No.-

The Use of MR Perfusion Imaging in the Evaluation of Tumor Progression in Gliomas

Snelling, Brian,Shah, Ashish H.,Buttrick, Simon,Benveniste, Ronald The Korean Neurosurgical Society 2017 Journal of Korean neurosurgical society Vol.60 No.1

Objective : Diagnosing tumor progression and pseudoprogression remains challenging for many clinicians. Accurate recognition of these findings remains paramount given necessity of prompt treatment. However, no consensus has been reached on the optimal technique to discriminate tumor progression. We sought to investigate the role of magnetic resonance perfusion (MRP) to evaluate tumor progression in glioma patients. Methods : An institutional retrospective review of glioma patients undergoing MRP with concurrent clinical follow up visit was performed. MRP was evaluated in its ability to predict tumor progression, defined clinically or radiographically, at concurrent clinical visit and at follow up visit. The data was then analyzed based on glioma grade and subtype. Resusts : A total of 337 scans and associated clinical visits were reviewed from 64 patients. Sensitivity, specificity, positive and negative predictive value were reported for each tumor subtype and grade. The sensitivity and specificity for high-grade glioma were 60.8% and 87.8% respectively, compared to low-grade glioma which were 85.7% and 89.0% respectively. The value of MRP to assess future tumor progression within 90 days was 46.9% (sensitivity) and 85.0% (specificity). Conclusion : Based on our retrospective review, we concluded that adjunct imaging modalities such as MRP are necessary to help diagnose clinical disease progression. However, there is no clear role for stand-alone surveillance MRP imaging in glioma patients especially to predict future tumor progression. It is best used as an adjunctive measure in patients in whom progression is suspected either clinically or radiographically.