• 제목/요약/키워드: Dean

검색결과 227건 처리시간 0.032초

곡률비가 다양한 코일 튜브에서의 열전달현상에 관한 연구 (A Study on the Heat Transfer Phenomena in Coiled Tubes with Variable Curvature Ratios)

  • 한규일;박종운
    • 대한기계학회논문집B
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    • 제22권11호
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    • pp.1509-1520
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    • 1998
  • An experiment was carried out for the fully developed turbulent flow of water in tube coils on the condition of uniform heat flux. The present work was conducted for various ranges for Dean number(1794~1321), Prandtl number (2.5~4.5), curvature ratio parameters (22~60). Heat transfer to steady viscous flow in coiled tubes of circular cross section was studied for fully developed velocity and temperature fields under the thermal boundary condition of uniform heat flux. The peripherally local Nusselt number correlated as a function of Dean and Prandtl numbers. We studied the flow in heat coiled tubes under the influence of both centrifugal and buoyancy forces in order to gain insight into the flow pattern. In the present study, we obtained three emperical formulas, $Nu_v=0.0231Re^{0.84}Pr^{0.4}(a/R)^{0.13}$ (vertical) $Nu_c=0.0241Re^{0.86}Pr^{0.4}(a/R)^{0.08}$ (corrugated) $Nu_h=0.0227Re^{0.84}Pr^{0.4}(a/R)^{0.09}$ (horizontal).

곡관덕트내의 입구영역에서 난류 맥동유도의 유동특성 (Flows Characteristics of Developing Turbulent Pulsating Flows in a curved Square Duct)

  • 봉태근
    • Journal of Advanced Marine Engineering and Technology
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    • 제23권4호
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    • pp.533-542
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    • 1999
  • In this study the flow characteristics of developing turbulent pulsating flows in a square-sec-tional 180。 curved duct are investigated experimentally. The experimental study of air flow in a square-sectional curved duct is carried out to measure axial velocity distribution secondary flow velocity profiles and wall shear stress distributions by using a Laser Doppler Velocimetry system with the data acquisition and processing system of Rotating Machinery Resolver (RMR) and PHASE software at the entrance region of the duct which is divided into 7 sections from the inlet(${{\o}}=0_{\circ}$) to the outlet (${{\o}}=180_{\circ}$) in $30_{\circ}$ intervals. The results obtained from the study are summarized as follows: (1) The time-averaged critical Dean number of turbulent pulsating flow(De ta, cr) is greater than $75{\omega}+$ It is understood that the critical Dean number and the critical Reynolds number are related to the dimensionless angular frequency in a curved duct. (2) Axial velocity profiles of turbulent pulsating flows are of an annular type similar to those of turbulent stead flows. (3) Secondary flows of trubulent pulsating flows are strong and complex at the entrance region. As velocity amplitudes(A1) become larger secondary flows become stronger. (4) Wall shear stress distributions of turbulent pulsating flows in a square-sectional $180_{\circ}$ curved duct are exposed variously in the outer wall and are stabilized in the inner wall without regard to the phase angle.

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Roles of the Faculty and Librarian in the Collaborative Relationships at Vietnamese Universities: A Qualitative Methodology

  • Nguyen, Lan Thi;Tuamsuk, Kulthida
    • Journal of Information Science Theory and Practice
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    • 제8권1호
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    • pp.33-44
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    • 2020
  • This article is a part of a doctoral research project on developing the faculty-librarian collaboration model to support learning and research at Vietnamese universities. The findings of this study have crucial significance in drawing a broader view of the importance of faculty-librarian collaboration and the roles of such collaborators at Vietnamese universities. Qualitative methodology was used to formulate related topics and achieve these research objectives. Semi-structured interviews were carried out at four universities in Vietnam with three key informants, including the faculty, librarian, and administrators (dean/vice dean of faculty, director/deputy director of the library). From March to April 2019, researchers conducted 29 interviews with three participant groups. The striking results of this research showed that the faculty and librarians realized the significance of a collaborative relationship and expect that Vietnamese universities will design and deploy a model to boost the effectiveness of this collaboration. Besides this, the study found that the collaborators play certain important roles within the collaborative relationship, for instance, that of reference, coordinator, special lecturer, cooperator, and information user.

Inertial Microfluidics-Based Cell Sorting

  • Kim, Ga-Yeong;Han, Jong-In;Park, Je-Kyun
    • BioChip Journal
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    • 제12권4호
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    • pp.257-267
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    • 2018
  • Inertial microfluidics has attracted significant attention in recent years due to its superior benefits of high throughput, precise control, simplicity, and low cost. Many inertial microfluidic applications have been demonstrated for physiological sample processing, clinical diagnostics, and environmental monitoring and cleanup. In this review, we discuss the fundamental mechanisms and principles of inertial migration and Dean flow, which are the basis of inertial microfluidics, and provide basic scaling laws for designing the inertial microfluidic devices. This will allow end-users with diverse backgrounds to more easily take advantage of the inertial microfluidic technologies in a wide range of applications. A variety of recent applications are also classified according to the structure of the microchannel: straight channels and curved channels. Finally, several future perspectives of employing fluid inertia in microfluidic-based cell sorting are discussed. Inertial microfluidics is still expected to be promising in the near future with more novel designs using various shapes of cross section, sheath flows with different viscosities, or technologies that target micron and submicron bioparticles.

미국병원시찰기-인터뷰-하버드(Harvard)의 의대 자원개발 학장 Jeffrey Newton

  • 대한병원협회
    • 대한병원협회지
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    • 제35권1호통권299호
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    • pp.108-111
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    • 2006
  • 본고는 고대의료원 미국 벤치마킹팀이 하버드 의대 방문 당시 부대수익사업과 행정부서 등이 입주해 있는 [랜드마크 센터(Landmark Center)]를 방문해 미국 및 하버드의 기부금 모집에 대해 인터뷰한 내용을 정리한 것이다. 인터뷰에 응해준 Jeffrey Newton 학장은 미국 마이애미 대학, 존스홉킨스 의과대학, 그리고 하버드 의대 등 미국 최고의 명문대학에서 자원개발(Development) 업무만을 담당해온 기금조성(Fundraising)전문가로 약 3년전 존스홉킨스 의과대학에서 하버드 의대로 옮겨와 펀드레이징 담당 학장(Dean for Development)을 맡고 있다

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Transient Forces on Pipe Bends by the Propagation of Pressure Wave

  • Woo, Hyo-Seop;Papadakis, C.N.;Kim, Won
    • Korean Journal of Hydrosciences
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    • 제6권
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    • pp.99-105
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    • 1995
  • External forecs acting on a pipe bend change when a transient pressure wave propagates through the bend. Analytical expressions are derived to compute the changes of these forces which depend mainly on static pressure rather than fluid momentum. This analysis reveals that the change of the vertical component of the force acting on a pipe bend with an angle larger than 90 may reverse in direction during the passage of a pressure wave through the bend.

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ANCHOR MOORING LINE ANALYSIS IN COHESIVE SEAFLOOR

  • Sangchul Bang
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2000년도 봄 학술발표회 논문집
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    • pp.58-76
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    • 2000
  • An analytical solution method capable of determining the geometric configuration and developed tensile forces of mooring lines associated with fixed plate/pile or drag anchors is presented. The solution method, satisfying complete equilibrium conditions, is capable of analyzing multi-segmented mooring lines that can consist of either chains, cables, or wires embedded in layered seafloor soils. Centrifuge model tests and full -scale field tests were used to calibrate and validate the analytical solution.

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PRIMITIVE/SEIFERT KNOTS WHICH ARE NOT TWISTED TORUS KNOT POSITION

  • Kang, Sungmo
    • 호남수학학술지
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    • 제35권4호
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    • pp.775-791
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    • 2013
  • The twisted torus knots and the primitive/Seifert knots both lie on a genus 2 Heegaard surface of $S^3$. In [5], J. Dean used the twisted torus knots to provide an abundance of examples of primitive/Seifert knots. Also he showed that not all twisted torus knots are primitive/Seifert knots. In this paper, we study the other inclusion. In other words, it shows that not all primitive/Seifert knots are twisted torus knot position. In fact, we give infinitely many primitive/Seifert knots that are not twisted torus knot position.

Prosthodontic rehabilitation of a patient with bilateral auricular deformity

  • Mantri, Sneha Shivkumar;Thombre, Ram U.;Pallavi, Daigavane
    • The Journal of Advanced Prosthodontics
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    • 제3권2호
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    • pp.101-105
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    • 2011
  • Maxillofacial prosthodontics is an art and science which provides life like appearance to the person with facial deformity. Maxillofacial prosthetic rehabilitation for acquired defects has become more complex and sophisticated with advancement in techniques and materials. This case report describes the clinical and laboratory procedure for fabricating an auricular prosthesis for a patient with trauma related bilateral auricular deformity. Ear prosthesis was fabricated in two parts taking retention from external auditory canal.

Advances in Imaging of Subsurface Archaeology using GPR

  • Dean, Goodman;Yasushi, Nishimur;Kent, Schneider;Salvadore, Piro;Hiromichi, Hongo;Noriaki, Higashi
    • 지구물리
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    • 제7권3호
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    • pp.161-170
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    • 2004
  • Examples of GPR survey results at a variety of archaeological sites are presented. Several new analyses which include static corrections for the tilt of the GPR antenna are shown for imaging of burial mounds with significant topography. Example archaeological site plans developed from GPR remote sensing of Roman and Japanese sites are given. The first completely automated GPR survey, using only Global Positioning Satellite navigation to create 3D data volumes, is employed for a site in Louisiana to detect lost graves of the Choctaw Indian Tribe.

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