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Sample records for rectangular mindlin plates

  1. Hermitian Mindlin Plate Wavelet Finite Element Method for Load Identification

    Directory of Open Access Journals (Sweden)

    Xiaofeng Xue

    2016-01-01

    Full Text Available A new Hermitian Mindlin plate wavelet element is proposed. The two-dimensional Hermitian cubic spline interpolation wavelet is substituted into finite element functions to construct frequency response function (FRF. It uses a system’s FRF and response spectrums to calculate load spectrums and then derives loads in the time domain via the inverse fast Fourier transform. By simulating different excitation cases, Hermitian cubic spline wavelets on the interval (HCSWI finite elements are used to reverse load identification in the Mindlin plate. The singular value decomposition (SVD method is adopted to solve the ill-posed inverse problem. Compared with ANSYS results, HCSWI Mindlin plate element can accurately identify the applied load. Numerical results show that the algorithm of HCSWI Mindlin plate element is effective. The accuracy of HCSWI can be verified by comparing the FRF of HCSWI and ANSYS elements with the experiment data. The experiment proves that the load identification of HCSWI Mindlin plate is effective and precise by using the FRF and response spectrums to calculate the loads.

  2. Energy flow analysis of out-of-plane vibration in coplanar coupled finite Mindlin plates

    Directory of Open Access Journals (Sweden)

    Young-Ho Park

    2015-01-01

    Full Text Available : In this paper, an Energy Flow Analysis (EFA for coplanar coupled Mindlin plates was performed to estimate their dynamic responses at high frequencies. Mindlin plate theory can consider the effects of shear distortion and rotatory inertia, which are very important at high frequencies. For EFA for coplanar coupled Mindlin plates, the wave transmission and reflection relationship for progressing out-of-plane waves (out-of-plane shear wave, bending dominant flexural wave, and shear dominant flexural wave in coplanar coupled Mindlin plates was newly derived. To verify the validity of the EFA results, numerical analyses were performed for various cases where coplanar coupled Mindlin plates are excited by a harmonic point force, and the energy flow solutions for coplanar coupled Mindlin plates were compared with the classical solutions in the various conditions.

  3. Size-dependent vibrations of post-buckled functionally graded Mindlin rectangular microplates

    Directory of Open Access Journals (Sweden)

    R. Ansari

    Full Text Available In this paper, the free vibration behavior of post-buckled functionally graded (FG Mindlin rectangular microplates are described based on the modified couple stress theory (MCST. This theory enables the consideration of the size-effect through introducing material length scale parameters. The FG microplates made of a mixture of metal and ceramic are considered whose volume fraction of components is expressed by a power law function. By means of Hamilton's principle, the nonlinear governing equations and associated boundary conditions are derived for FG micro-plates in the postbuckling domain. The governing equations and boundary conditions are then discretized by using the generalized differential quadrature (GDQ method before solving numerically by the pseudo-arclength continuation technique. In the solution procedure, the postbuckling problem of microplates is investigated first. Afterwards, the free vibration of microplates around the buckled configuration is discussed. The effects of dimensionless length scale parameter, material gradient index and aspect ratio on the on the postbuckling path and frequency of FG microplates subject to arbitrary edge supports are thoroughly discussed.

  4. Reissner-Mindlin plate model with uncertain input data

    Czech Academy of Sciences Publication Activity Database

    Hlaváček, Ivan; Chleboun, J.

    2014-01-01

    Roč. 17, Jun (2014), s. 71-88 ISSN 1468-1218 Institutional support: RVO:67985840 Keywords : Reissner-Mindlin model * orthotropic plate Subject RIV: BA - General Mathematics Impact factor: 2.519, year: 2014 http://www.sciencedirect.com/science/article/pii/S1468121813001077

  5. A new discrete Kirchhoff-Mindlin element based on Mindlin-Reissner plate theory and assumed shear strain fields. I - An extended DKT element for thick-plate bending analysis. II - An extended DKQ element for thick-plate bending analysis

    Science.gov (United States)

    Katili, Irwan

    1993-06-01

    A new three-node nine-degree-of-freedom triangular plate bending element is proposed which is valid for the analysis of both thick and thin plates. The element, called the discrete Kirchhoff-Mindlin triangle (DKMT), has a proper rank, passes the patch test for thin and thick plates in an arbitrary mesh, and is free of shear locking. As an extension of the DKMT element, a four-node element with 3 degrees of freedom per node is developed. The element, referred to as DKMQ (discrete Kirchhoff-Mindlin quadrilateral) is found to provide good results for both thin and thick plates without any compatibility problems.

  6. Discrete singular convolution method for the analysis of Mindlin plates on elastic foundations

    International Nuclear Information System (INIS)

    Civalek, Omer; Acar, Mustafa Hilmi

    2007-01-01

    The method of discrete singular convolution (DSC) is used for the bending analysis of Mindlin plates on two-parameter elastic foundations for the first time. Two different realizations of singular kernels, such as the regularized Shannon's delta (RSD) kernel and Lagrange delta sequence (LDS) kernel, are selected as singular convolution to illustrate the present algorithm. The methodology and procedures are presented and bending problems of thick plates on elastic foundations are studied for different boundary conditions. The influence of foundation parameters and shear deformation on the stress resultants and deflections of the plate have been investigated. Numerical studies are performed and the DSC results are compared well with other analytical solutions and some numerical results

  7. Vibration analysis of orthotropic circular and elliptical nano-plates embedded in elastic medium based on nonlocal Mindlin plate theory and using Galerkin method

    International Nuclear Information System (INIS)

    Anjomshoa, Amin; Tahani, Masoud

    2016-01-01

    In the present study a continuum model based on the nonlocal elasticity theory is developed for free vibration analysis of embedded ortho tropic thick circular and elliptical nano-plates rested on an elastic foundation. The elastic foundation is considered to behave like a Pasternak type of foundations. Governing equations for vibrating nano-plate are derived according to the Mindlin plate theory in which the effects of shear deformations of nano-plate are also included. The Galerkin method is then employed to obtain the size dependent natural frequencies of nano-plate. The solution procedure considers the entire nano-plate as a single super-continuum element. Effect of nonlocal parameter, lengths of nano-plate, aspect ratio, mode number, material properties, thickness and foundation on circular frequencies are investigated. It is seen that the nonlocal frequencies of the nano-plate are smaller in comparison to those from the classical theory and this is more pronounced for small lengths and higher vibration modes. It is also found that as the aspect ratio increases or the nanoplate becomes more elliptical, the small scale effect on natural frequencies increases. Further, it is observed that the elastic foundation decreases the influence of nonlocal parameter on the results. Since the effect of shear deformations plays an important role in vibration analysis and design of nano-plates, by predicting smaller values for fundamental frequencies, the study of these nano-structures using thick plate theories such as Mindlin plate theory is essential.

  8. Asymptotical construction of a fully coupled, Reissner–Mindlin model for piezoelectric composite plates

    International Nuclear Information System (INIS)

    Liao Lin; Yu Wenbin

    2008-01-01

    The variational asymptotic method is used to construct a fully coupled Reissner–Mindlin model for piezoelectric composite plates with some surfaces parallel to the reference surface coated with electrodes. Taking advantage of the smallness of the plate thickness, we asymptotically split the original three-dimensional electromechanical problem into a one-dimensional through-the-thickness analysis and a two-dimensional plate analysis. The through-the-thickness analysis serves as a link between the original three-dimensional analysis and the plate analysis by providing a constitutive model for the plate analysis and recovering the three-dimensional field variables in terms of two-dimensional plate global responses. The present theory is implemented into the computer program VAPAS (variational asymptotic plate and shell analysis). The resulting model is as simple as an equivalent single-layer, first-order shear deformation theory with accuracy comparable to higher-order layerwise theories. Various numerical examples have been used to validate the present model

  9. Analysis of the discontinuous Petrov-Galerkin method with optimal test functions for the Reissner-Mindlin plate bending model

    KAUST Repository

    Calo, Victor M.; Collier, Nathan; Niemi, Antti H.

    2014-01-01

    We analyze the discontinuous Petrov-Galerkin (DPG) method with optimal test functions when applied to solve the Reissner-Mindlin model of plate bending. We prove that the hybrid variational formulation underlying the DPG method is well-posed (stable

  10. EXACT SOLUTION FOR TEMPERATURE-DEPENDENT BUCKLING ANALYSIS OF FG-CNT-REINFORCED MINDLIN PLATES

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    Seyed Mohammad Mousavi

    2016-03-01

    Full Text Available This research deals with the buckling analysis of nanocomposite polymeric temperature-dependent plates reinforced by single-walled carbon nanotubes (SWCNTs. For the carbon-nanotube reinforced composite (CNTRC plate, uniform distribution (UD and three types of functionally graded (FG distribution patterns of SWCNT reinforcements are assumed. The material properties of FG-CNTRC plate are graded in the thickness direction and estimated based on the rule of mixture. The CNTRC is located in a elastic medium which is simulated with temperature-dependent Pasternak medium. Based on orthotropic Mindlin plate theory, the governing equations are derived using Hamilton’s principle and solved by Navier method. The influences of the volume fractions of carbon nanotubes, elastic medium, temperature and distribution type of CNTs are considered on the buckling of the plate. Results indicate that CNT distribution close to top and bottom are more efficient than those distributed nearby the mid-plane for increasing the stiffness of plates.

  11. A New Triangular Hybrid Displacement Function Element for Static and Free Vibration Analyses of Mindlin-Reissner Plate

    Directory of Open Access Journals (Sweden)

    Jun-Bin Huang

    Full Text Available Abstract A new 3-node triangular hybrid displacement function Mindlin-Reissner plate element is developed. Firstly, the modified variational functional of complementary energy for Mindlin-Reissner plate, which is eventually expressed by a so-called displacement function F, is proposed. Secondly, the locking-free formulae of Timoshenko’s beam theory are chosen as the deflection, rotation, and shear strain along each element boundary. Thirdly, seven fundamental analytical solutions of the displacement function F are selected as the trial functions for the assumed resultant fields, so that the assumed resultant fields satisfy all governing equations in advance. Finally, the element stiffness matrix of the new element, denoted by HDF-P3-7β, is derived from the modified principle of complementary energy. Together with the diagonal inertia matrix of the 3-node triangular isoparametric element, the proposed element is also successfully generalized to the free vibration problems. Numerical results show that the proposed element exhibits overall remarkable performance in all benchmark problems, especially in the free vibration analyses.

  12. Potential recovery for Reissner--Mindlin and Kirchhoff--Love plate models using global Carleman estimates

    International Nuclear Information System (INIS)

    Osses, Axel; Palacios, Benjamín

    2013-01-01

    In this paper, we consider two linear plate models, namely the Reissner–Mindlin system (R–M) and the Kirchhoff–Love equation (K–L), which come from linear elasticity. We prove global Carleman inequalities for both models with boundary observations and under a suitable hypothesis on the parameters. We use these estimates to study the inverse problem of recovering a spatially dependent potential from knowledge of Neumann boundary data. We obtain L 2 -Lipschitz stability for K–L and H 1 -Lipschitz stability for R–M under the assumption that the potentials are equal at the boundary. (paper)

  13. A functional-type a posteriori error estimate of approximate solutions for Reissner-Mindlin plates and its implementation

    Science.gov (United States)

    Frolov, Maxim; Chistiakova, Olga

    2017-06-01

    Paper is devoted to a numerical justification of the recent a posteriori error estimate for Reissner-Mindlin plates. This majorant provides a reliable control of accuracy of any conforming approximate solution of the problem including solutions obtained with commercial software for mechanical engineering. The estimate is developed on the basis of the functional approach and is applicable to several types of boundary conditions. To verify the approach, numerical examples with mesh refinements are provided.

  14. Vectorization and parallelization of the finite strip method for dynamic Mindlin plate problems

    Science.gov (United States)

    Chen, Hsin-Chu; He, Ai-Fang

    1993-01-01

    The finite strip method is a semi-analytical finite element process which allows for a discrete analysis of certain types of physical problems by discretizing the domain of the problem into finite strips. This method decomposes a single large problem into m smaller independent subproblems when m harmonic functions are employed, thus yielding natural parallelism at a very high level. In this paper we address vectorization and parallelization strategies for the dynamic analysis of simply-supported Mindlin plate bending problems and show how to prevent potential conflicts in memory access during the assemblage process. The vector and parallel implementations of this method and the performance results of a test problem under scalar, vector, and vector-concurrent execution modes on the Alliant FX/80 are also presented.

  15. direct method of analysis of an isotropic rectangular plate direct

    African Journals Online (AJOL)

    eobe

    This work evaluates the static analysis of an isotropic rectangular plate with various the static analysis ... method according to Ritz is used to obtain the total potential energy of the plate by employing the used to ..... for rectangular plates analysis, as the behavior of the ... results obtained by previous research work that used.

  16. Natural Vibration Analysis of Clamped Rectangular Orthotropic Plates

    Science.gov (United States)

    dalaei, m.; kerr, a. d.

    The natural vibrations of clamped rectangular orthotropic plates are analyzed using the extended Kantorovich method. The developed iterative scheme converges very rapidly to the final result. The obtained natural frequencies are evaluated for a square plate made of Kevlar 49 Epoxy and the obtained results are compared with those published by Kanazawa and Kawai, and by Leissa. The agreement was found to be very close. As there are no exact analytical solutions for clamped rectangular plates, the generated closed form expression for the natural modes, and the corresponding natural frequencies, are very suitable for use in engineering analyses.

  17. Free vibration characteristics analysis of rectangular plate with rectangular opening based on Fourier series method

    Directory of Open Access Journals (Sweden)

    WANG Minhao

    2017-08-01

    Full Text Available Plate structures with openings are common in many engineering structures. The study of the vibration characteristics of such structures is directly related to the vibration reduction, noise reduction and stability analysis of an overall structure. This paper conducts research into the free vibration characteristics of a thin elastic plate with a rectangular opening parallel to the plate in an arbitrary position. We use the improved Fourier series to represent the displacement tolerance function of the rectangular plate with an opening. We can divide the plate into an eight zone plate to simplify the calculation. We then use linear springs, which are uniformly distributed along the boundary, to simulate the classical boundary conditions and the boundary conditions of the boundaries between the regions. According to the energy functional and variational method, we can obtain the overall energy functional. We can also obtain the generalized eigenvalue matrix equation by studying the extremum of the unknown improved Fourier series expansion coefficients. We can then obtain the natural frequencies and corresponding vibration modes of the rectangular plate with an opening by solving the equation. We then compare the calculated results with the finite element method to verify the accuracy and effectiveness of the method proposed in this paper. Finally, we research the influence of the boundary condition, opening size and opening position on the vibration characteristics of a plate with an opening. This provides a theoretical reference for practical engineering application.

  18. Free vibration analysis of rectangular plates with central cutout

    Directory of Open Access Journals (Sweden)

    Kanak Kalita

    2016-12-01

    Full Text Available A nine-node isoparametric plate element in conjunction with first-order shear deformation theory is used for free vibration analysis of rectangular plates with central cutouts. Both thick and thin plate problems are solved for various aspect ratios and boundary conditions. In this article, primary focus is given to the effect of rotary inertia on natural frequencies of perforated rectangular plates. It is found that rotary inertia has significant effect on thick plates, while for thin plates the rotary inertia term can be ignored. It is seen that the numerical convergence is very rapid and based on comparison with experimental and analytical data from literature, it is proposed that the present formulation is capable of yielding highly accurate results. Finally, some new numerical solutions are provided here, which may serve as benchmark for future research on similar problems.

  19. Elastic stability of thick auxetic plates

    International Nuclear Information System (INIS)

    Lim, Teik-Cheng

    2014-01-01

    Auxetic materials and structures exhibit a negative Poisson’s ratio while thick plates encounter shear deformation, which is not accounted for in classical plate theory. This paper investigates the effect of a negative Poisson’s ratio on thick plates that are subjected to buckling loads, taking into consideration the shear deformation using Mindlin plate theory. Using a highly accurate shear correction factor that allows for the effect of Poisson’s ratio, the elastic stability of circular and square plates are evaluated in terms of dimensionless parameters, namely the Mindlin-to-Kirchhoff critical buckling load ratio and Mindlin critical buckling load factors. Results for thick square plates reveal that both parameters increase as the Poisson’s ratio becomes more negative. In the case of thick circular plates, the Mindlin-to-Kirchhoff critical buckling load ratios and the Mindlin critical buckling load factors increase and decrease, respectively, as the Poisson’s ratio becomes more negative. The results obtained herein show that thick auxetic plates behave as thin conventional plates, and therefore suggest that the classical plate theory can be used to evaluate the elastic stability of thick plates if the Poisson’s ratio of the plate material is sufficiently negative. The results also suggest that materials with highly negative Poisson’s ratios are recommended for square plates, but not circular plates, that are subjected to buckling loads. (paper)

  20. analytical bending solution of all clamped isotropic rectangular plate

    African Journals Online (AJOL)

    HP

    PLATE ON WINKLER'S FOUNDATION USING CHARACTERISTIC. ORTHOGONAL ... foundations, storage tanks, swimming pools, floor system of buildings, highways ..... “Energy Methods in Theory of Rectangular Plates. (use of Polynomial ...

  1. Natural Frequency of F.G. Rectangular Plate by Shear Deformation Theory

    International Nuclear Information System (INIS)

    Shahrjerdi, Ali; Sapuan, S M; Shahzamanian, M M; Mustapha, F; Zahari, R; Bayat, M

    2011-01-01

    Natural frequency of functionally graded (F.G.) rectangular plate is carried out by using second-order shear deformation theory (SSDT). The material properties of functionally graded rectangular plates, except the Poisson's ratio, are assumed to vary continuously through the thickness of the plate in accordance with the exponential law distribution. The equations of motion are obtained by energy method. Numerical results for functionally graded plates are given in dimensionless graphical forms and the effects of material properties on natural frequency are determined.

  2. Modeling and Chaotic Dynamics of the Laminated Composite Piezoelectric Rectangular Plate

    Directory of Open Access Journals (Sweden)

    Minghui Yao

    2014-01-01

    Full Text Available This paper investigates the multipulse heteroclinic bifurcations and chaotic dynamics of a laminated composite piezoelectric rectangular plate by using an extended Melnikov method in the resonant case. According to the von Karman type equations, Reddy’s third-order shear deformation plate theory, and Hamilton’s principle, the equations of motion are derived for the laminated composite piezoelectric rectangular plate with combined parametric excitations and transverse excitation. The method of multiple scales and Galerkin’s approach are applied to the partial differential governing equation. Then, the four-dimensional averaged equation is obtained for the case of 1 : 3 internal resonance and primary parametric resonance. The extended Melnikov method is used to study the Shilnikov type multipulse heteroclinic bifurcations and chaotic dynamics of the laminated composite piezoelectric rectangular plate. The necessary conditions of the existence for the Shilnikov type multipulse chaotic dynamics are analytically obtained. From the investigation, the geometric structure of the multipulse orbits is described in the four-dimensional phase space. Numerical simulations show that the Shilnikov type multipulse chaotic motions can occur. To sum up, both theoretical and numerical studies suggest that chaos for the Smale horseshoe sense in motion exists for the laminated composite piezoelectric rectangular plate.

  3. 10 years of mindlines: a systematic review and commentary.

    Science.gov (United States)

    Wieringa, Sietse; Greenhalgh, Trisha

    2015-04-09

    In 2004, Gabbay and le May showed that clinicians generally base their decisions on mindlines-internalised and collectively reinforced tacit guidelines-rather than consulting written clinical guidelines. We considered how the concept of mindlines has been taken forward since. We searched databases from 2004 to 2014 for the term 'mindline(s)' and tracked all sources citing Gabbay and le May's 2004 article. We read and re-read papers to gain familiarity and developed an interpretive analysis and taxonomy by drawing on the principles of meta-narrative systematic review. In our synthesis of 340 papers, distinguished between authors who used mindlines purely in name ('nominal' view) sometimes dismissing them as a harmful phenomenon, and authors who appeared to have understood the term's philosophical foundations. The latter took an 'in-practice' view (studying how mindlines emerge and spread in real-world settings), a 'theoretical and philosophical' view (extending theory) or a 'solution focused' view (exploring how to promote and support mindline development). We found that it is not just clinicians who develop mindlines: so do patients, in face-to-face and (potentially) online communities. Theoretical publications on mindlines have continued to challenge the rationalist assumptions of evidence-based medicine (EBM). Conventional EBM assumes a single, knowable reality and seeks to strip away context to generate universal predictive rules. In contrast, mindlines are predicated on a more fluid, embodied and intersubjective view of knowledge; they accommodate context and acknowledge multiple realities. When considering how knowledge spreads, the concept of mindlines requires us to go beyond the constraining notions of 'dissemination' and 'translation' to study tacit knowledge and the interactive human processes by which such knowledge is created, enacted and shared. Solution-focused publications described mindline-promoting initiatives such as relationship

  4. Rectangular Gusset Plate Behaviour in Cold-Formed I-Type Steel Connections

    Directory of Open Access Journals (Sweden)

    Bučmys Ž.

    2017-06-01

    Full Text Available Cold-formed structure connections utilizing gusset plates are usually semi-rigid. This paper investigates the behaviours of rectangular gusset plates in cold-formed connections of elements whose columns and beams are made with lipped back-to-back C-sections. Methods of calculating strength and stiffness are necessary for such semi-rigid joints. The main task of this paper is to determine a method capable of calculating these characteristics. The proposed analytical method could then be easily adapted to the component method that is described in part 1993-1-8 of the Eurocode. This method allows us to calculate both the strength and stiffness of rectangular gusset plates, assuming that the joint deforms only in plane. This method of design moment resistance calculation was presented taking into account that an entire cross-section shall reach its yield stress. A technique of stiffness calculation was presented investigating the sum of deformations acquired at the bending moment and from shear forces which are transmitted from each beam bolt group. Calculation results according to the suggested method show good agreement of laboratory experimental results of specimens with numerical simulations. Two specimens of beam-to-column connections were tested in the laboratory. Lateral supports were used on the specimens to prevent lateral displacements in order to better investigate the behaviour of the rectangular gusset plate in plane. Experiments were simulated by modelling rectangular gusset plates using standard finite element software ANSYS Workbench 14.0. Three-dimensional solid elements were used for modelling and both geometric and material nonlinear analysis was performed.

  5. VIBRATION CONTROL OF RECTANGULAR CROSS-PLY FRP PLATES USING PZT MATERIALS

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    DILEEP KUMAR K

    2017-12-01

    Full Text Available Piezoelectric materials are extensively employed in the field of structures for condition monitoring, smart control and testing applications. The piezoelectric patches are surface bonded to a composite laminate plate and used as vibration actuators. The coupling effects between the mechanical and electric properties of piezoelectric materials have drawn significant attention for their potential applications. In the present work, an analytical solution of the vibration response of a simply supported laminate rectangular plate under time harmonic electrical loading is obtained and a concept is developed for an approximate dynamic model to the vibration response of the simply supported orthotropic rectangular plates excited by a piezoelectric patch of variable rectangular geometry and location. A time harmonic electric voltages with the same magnitude and opposite sign are applied to the two symmetric piezoelectric actuators, which results in the bending moment on the plate. The main objective of the work is to obtain an analytical solution for the vibration amplitude of composite plate predicted from plate theory. The results demonstrate that the vibration modes can be selectively excited and the geometry of the PZTactuator shape remarkably affects the distribution of the response among modes. Thus according to the desired degree shape control it is possible to tailor the shape, size and properly designed control algorithm of the actuator to either excite or suppress particular modes.

  6. Simplified Procedure For The Free Vibration Analysis Of Rectangular Plate Structures With Holes And Stiffeners

    Directory of Open Access Journals (Sweden)

    Cho Dae Seung

    2015-04-01

    Full Text Available Thin and thick plates, plates with holes, stiffened panels and stiffened panels with holes are primary structural members in almost all fields of engineering: civil, mechanical, aerospace, naval, ocean etc. In this paper, a simple and efficient procedure for the free vibration analysis of such elements is presented. It is based on the assumed mode method and can handle different plate thickness, various shapes and sizes of holes, different framing sizes and types as well as different combinations of boundary conditions. Natural frequencies and modes are determined by solving an eigenvalue problem of a multi-degree-of-freedom system matrix equation derived by using Lagrange’s equations. Mindlin theory is applied for a plate and Timoshenko beam theory for stiffeners. The applicability of the method in the design procedure is illustrated with several numerical examples obtained by the in-house developed code VAPS. Very good agreement with standard commercial finite element software is achieved.

  7. Size-dependent bending, buckling and vibration of higher-order shear deformable magneto-electro-thermo-elastic rectangular nanoplates

    Science.gov (United States)

    Gholami, Raheb; Ansari, Reza; Gholami, Yousef

    2017-06-01

    The aim of the present study is to propose a unified size-dependent higher-order shear deformable plate model for magneto-electro-thermo-elastic (METE) rectangular nanoplates by adopting the nonlocal elasticity theory to capture the size effect, and by utilizing a generalized shape function to consider the effects of transverse shear deformation and rotary inertia. By considering various shape functions, the proposed plate model can be reduced to the nonlocal plate model based upon the Kirchhoff, Mindlin and Reddy plate theories, as well as the parabolic, trigonometric, hyperbolic and exponential shear deformation plate theories. The governing equations of motion and corresponding boundary conditions of METE nanoplates subjected to external in-plane, transverse loads as well as magnetic, electric and thermal loadings, are obtained using Hamilton’s principle. Then, as in some case studies, the static bending, buckling, and free vibration characteristics of simply-supported METE rectangular nanoplates are investigated based upon the Navier solution approach. Numerical results are provided in order to investigate the influences of various parameters including the nondimensional nonlocal parameter, type of transverse loading, temperature change, applied voltage, and external magnetic potential on the mechanical behaviors of METE nanoplates. Furthermore, comparisons are made between the results predicted by different nonlocal plate models by utilizing the developed unified nonlocal plate model and selecting the associated shape functions. It is illustrated that by using the presented unified nonlocal plate model, the development of a nonlocal plate model based upon any existing higher-order shear deformable plate theory is a simple task.

  8. Integral transform solution of bending problem of clamped orthotropic rectangular plates

    International Nuclear Information System (INIS)

    An, C.; Gu, J.-J.; Su, J.

    2011-01-01

    The generalized integral transform technique (GITT) is employed to obtain an exact solution for the bending problem of fully clamped orthotropic rectangular plates. The use of the GITT approach in the analysis of the transverse deflection equation leads to a coupled system of fourth order differential equations in the dimensionless longitudinal spatial variable. The resulting transformed ODE system is then numerically solved by making use of the subroutine DBVPFD from IMSL Library. Numerical results with automatic global accuracy control are produced for different values of aspect ratio. Critical comparisons with previously reported numerical results are performed with excellent agreement. Several sets of reference results for clamped orthotropic rectangular plates are also provided for future covalidation purposes. (author)

  9. Resonant frequency function of thickness-shear vibrations of rectangular crystal plates.

    Science.gov (United States)

    Wang, Ji; Yang, Lijun; Pan, Qiaoqiao; Chao, Min-Chiang; Du, Jianke

    2011-05-01

    The resonant frequencies of thickness-shear vibrations of quartz crystal plates in rectangular and circular shapes are always required in the design and manufacturing of quartz crystal resonators. As the size of quartz crystal resonators shrinks, for rectangular plates we must consider effects of both length and width for the precise calculation of resonant frequency. Starting from the three-dimensional equations of wave propagation in finite crystal plates and the general expression of vibration modes, we obtained the relations between frequency and wavenumbers. By satisfying the major boundary conditions of the dominant thickness-shear mode, three wavenumber solutions are obtained and the frequency equation is constructed. It is shown the resonant frequency of thickness-shear mode is a second-order polynomial of aspect ratios. This conforms to known results in the simplest form and is applicable to further analytical and experimental studies of the frequency equation of quartz crystal resonators.

  10. Local and global nonlinear dynamics of a parametrically excited rectangular symmetric cross-ply laminated composite plate

    International Nuclear Information System (INIS)

    Ye Min; Lu Jing; Zhang Wei; Ding Qian

    2005-01-01

    The present investigation deals with nonlinear dynamic behavior of a parametrically excited simply supported rectangular symmetric cross-ply laminated composite thin plate for the first time. The governing equation of motion for rectangular symmetric cross-ply laminated composite thin plate is derived by using von Karman equation. The geometric nonlinearity and nonlinear damping are included in the governing equations of motion. The Galerkin approach is used to obtain a two-degree-of-freedom nonlinear system under parametric excitation. The method of multiple scales is utilized to transform the second-order non-autonomous differential equations to the first-order averaged equations. Using numerical method, the averaged equations are analyzed to obtain the steady state bifurcation responses. The analysis of stability for steady state bifurcation responses in laminated composite thin plate is also given. Under certain conditions laminated composite thin plate may have two or multiple steady state bifurcation solutions. Jumping phenomenon occurs in the steady state bifurcation solutions. The chaotic motions of rectangular symmetric cross-ply laminated composite thin plate are also found by using numerical simulation. The results obtained here demonstrate that the periodic, quasi-periodic and chaotic motions coexist for a parametrically excited fore-edge simply supported rectangular symmetric cross-ply laminated composite thin plate under certain conditions

  11. The problem of isotropic rectangular plate with four clamped edges

    Indian Academy of Sciences (India)

    of rectangular plates has been a subject of study in solid mechanics for more than a cen- .... loading is solved first, giving the deflection function for the strip case and .... The authors gratefully acknowledge the advice and encouragement of ...

  12. Analysis of the discontinuous Petrov-Galerkin method with optimal test functions for the Reissner-Mindlin plate bending model

    KAUST Repository

    Calo, Victor M.

    2014-01-01

    We analyze the discontinuous Petrov-Galerkin (DPG) method with optimal test functions when applied to solve the Reissner-Mindlin model of plate bending. We prove that the hybrid variational formulation underlying the DPG method is well-posed (stable) with a thickness-dependent constant in a norm encompassing the L2-norms of the bending moment, the shear force, the transverse deflection and the rotation vector. We then construct a numerical solution scheme based on quadrilateral scalar and vector finite elements of degree p. We show that for affine meshes the discretization inherits the stability of the continuous formulation provided that the optimal test functions are approximated by polynomials of degree p+3. We prove a theoretical error estimate in terms of the mesh size h and polynomial degree p and demonstrate numerical convergence on affine as well as non-affine mesh sequences. © 2013 Elsevier Ltd. All rights reserved.

  13. Fluid Flow and Infrared Image Analyses on Endwall Fitted with Short Rectangular Plate Fin

    Institute of Scientific and Technical Information of China (English)

    Kenyu OYAKAWA; Islam Md. DIDARUL; Minoru YAGA

    2006-01-01

    An experimental investigation is carried out to study fluid flow and heat transfer characteristics on the endwall fitted with arrays ( 7 × 7 ) of short rectangular plate fins of different pattern (co-angular and zigzag) for different pitch ratio. Experiments were conducted in a rectangular duct of 50 mm height for an air flow of Reynolds number ranged from 18750 to 62500 based on the equivalent diameter and air velocity of the duct. Infrared image analysis technique was employed to make clear the characteristics of local heat transfer coefficients on fin base, endwall and overall surface. Flow pattern around the short rectangular plates were visualized by inducing fluorescent dye in a water channel and longitudinal vortices were observed. Increasing the distance between plates in flow direction causes heat transfer enhancement for co-angular pattern, while decreasing the distance causes heat transfer enhancement for zigzag pattern. Zigzag pattern with pitch ratio 2 is found to be more effective in heat transfer enhancement than any other cases investigated.

  14. Transient thermal stresses in an orthotropic finite rectangular plate due to arbitrary surface heat-generations

    International Nuclear Information System (INIS)

    Sugano, Y.

    1980-01-01

    The transient thermal stresses in an orthotropic finite rectangular plate due to arbitrary surface heat-generations on two edges are studied by means of the Airy stress function. The purposes of this paper are to present a method of determing the transient thermal stresses in an orthographic rectangular plate with four edges of distinct thermal boundary condition of the third kind which exactly satisfy the traction-free conditions of shear stress over all boundaries including four corners of the plate, and to consider the effects of the anisotropies of material properties and the convective heat transfer on the upper and lower surfaces on the thermal stress distribution. (orig.)

  15. Free Vibration of Rectangular Plates with Attached Discrete Sprung Masses

    Directory of Open Access Journals (Sweden)

    Ding Zhou

    2012-01-01

    Full Text Available A direct approach is used to derive the exact solution for the free vibration of thin rectangular plates with discrete sprung masses attached. The plate is simply supported along two opposite edges and elastically supported along the two other edges. The elastic support can represent a range of boundary conditions from free to clamped supports. Considering only the compatibility of the internal forces between the plate and the sprung masses, the equations of the coupled vibration of the plate-spring-mass system are derived. The exact expressions for mode and frequency equations of the coupled vibration of the plate and sprung masses are determined. The solutions converge steadily and monotonically to exact values. The correctness and accuracy of the solutions are demonstrated through comparison with published results. A parametric study is undertaken focusing on the plate with one or two sprung masses. The results can be used as a benchmark for further investigation.

  16. Frequency response of rectangular plates with free-edge openings and carlings subjected to point excitation force and enforced displacement at boundaries

    Directory of Open Access Journals (Sweden)

    Dae Seung Cho

    2016-03-01

    Full Text Available In this paper, a numerical procedure for the natural vibration analysis of plates with openings and carlings based on the assumed mode method is extended to assess their forced response. Firstly, natural response of plates with openings and carlings is calculated from the eigenvalue equation derived by using Lagrange's equation of motion. Secondly, the mode superposition method is applied to determine frequency response. Mindlin theory is adopted for plate modelling and the effect of openings is taken into account by subtracting their potential and kinetic energies from the corresponding plate energies. Natural and frequency response of plates with openings and carlings subjected to point excitation force and enforced acceleration at boundaries, respectively, is analysed by using developed in-house code. For the validation of the developed method and the code, extensive numerical results, related to plates with different opening shape, carlings and boundary conditions, are compared with numerical data from the relevant literature and with finite element solutions obtained by general finite element tool.

  17. Buckling Analysis of Rectangular Plates with Variable Thickness Resting on Elastic Foundation

    International Nuclear Information System (INIS)

    Viswanathan, K K; Aziz, Z A; Navaneethakrishnan, P V

    2015-01-01

    Buckling of rectangular plates of variable thickness resting in elastic foundation is analysed using a quintic spline approximation technique. The thickness of the plate varies in the direction of one edge and the variations are assumed to be linear, exponential and sinusoidal. The plate is subjected to in plane load of two opposite edges. The buckling load and the mode shapes of buckling are computed from the eigenvalue problem that arises. Detailed parametric studies are made with different boundary conditions and the results are presented through the diagram and discussed

  18. Nonlocal free vibration in the pre- and post-buckled states of magneto-electro-thermo elastic rectangular nanoplates with various edge conditions

    Science.gov (United States)

    Ansari, R.; Gholami, R.

    2016-09-01

    Considering the small scale effect together with the influences of transverse shear deformation, rotary inertia and the magneto-electro-thermo-mechanical coupling, the linear free vibration of magneto-electro-thermo-elastic (METE) rectangular nanoplates with various edge supports in pre- and post-buckled states is investigated herein. It is assumed that the METE nanoplate is subjected to the external in-plane compressive loads in combination with magnetic, electric and thermal loads. The Mindlin plate theory, von Kármán hypothesis and the nonlocal theory are utilized to develop a size-dependent geometrically nonlinear plate model for describing the size-dependent linear and nonlinear mechanical characteristics of moderately thick METE rectangular nanoplates. The nonlinear governing equations and the corresponding boundary conditions are derived using Hamilton’s principle which are then discretized via the generalized differential quadrature method. The pseudo-arc length continuation approach is used to obtain the equilibrium postbuckling path of METE nanoplates. By the obtained postbuckling response, and taking a time-dependent small disturbance around the buckled configuration, and inserting them into the nonlinear governing equations, an eigenvalue problem is achieved from which the frequencies of pre- and post-buckled METE nanoplates can be calculated. The effects of nonlocal parameter, electric, magnetic and thermal loadings, length-to-thickness ratio and different boundary conditions on the free vibration response of METE rectangular nanoplates in the pre- and post-buckled states are highlighted.

  19. Nonlinear dynamics and control of a vibrating rectangular plate

    Science.gov (United States)

    Shebalin, J. V.

    1983-01-01

    The von Karman equations of nonlinear elasticity are solved for the case of a vibrating rectangular plate by meams of a Fourier spectral transform method. The amplification of a particular Fourier mode by nonlinear transfer of energy is demonstrated for this conservative system. The multi-mode system is reduced to a minimal (two mode) system, retaining the qualitative features of the multi-mode system. The effect of a modal control law on the dynamics of this minimal nonlinear elastic system is examined.

  20. Postbuckling Analysis Of A Rectangular Plate Loaded In Compression

    Directory of Open Access Journals (Sweden)

    Havran Jozef

    2015-12-01

    Full Text Available The stability analysis of a thin rectangular plate loaded in compression is presented. The nonlinear FEM equations are derived from the minimum total potential energy principle. The peculiarities of the effects of the initial imperfections are investigated using the user program. Special attention is paid to the influence of imperfections on the post-critical buckling mode. The FEM computer program using a 48 DOF element has been used for analysis. Full Newton-Raphson procedure has been applied.

  1. Vibration Analysis of Rectangular Plates with One or More Guided Edges via Bicubic B-Spline Method

    Directory of Open Access Journals (Sweden)

    W.J. Si

    2005-01-01

    Full Text Available A simple and accurate method is proposed for the vibration analysis of rectangular plates with one or more guided edges, in which bicubic B-spline interpolation in combination with a new type of basis cubic B-spline functions is used to approximate the plate deflection. This type of basis cubic B-spline functions can satisfy simply supported, clamped, free, and guided edge conditions with easy numerical manipulation. The frequency characteristic equation is formulated based on classical thin plate theory by performing Hamilton's principle. The present solutions are verified with the analytical ones. Fast convergence, high accuracy and computational efficiency have been demonstrated from the comparisons. Frequency parameters for 13 cases of rectangular plates with at least one guided edge, which are possible by approximate or numerical methods only, are presented. These results are new in literature.

  2. Thermal stresses in rectangular plates: variational and finite element solutions

    International Nuclear Information System (INIS)

    Laura, P.A.A.; Gutierrez, R.H.; Sanchez Sarmiento, G.; Basombrio, F.G.

    1978-01-01

    This paper deals with the development of an approximate method for the analysis of thermal stresses in rectangular plates (plane stress problem) and an evaluation of the relative accuracy of the finite element method. The stress function is expanded in terms of polynomial coordinate functions which identically satisfy the boundary conditions, and a variational approach is used to determine the expansion coefficients. The results are in good agreement with a finite element approach. (Auth.)

  3. Comparison of closed-form and finite-element solutions of thick laminated anisotropic rectangular plates

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, J N; Chao, W C [Virginia Polytechnic Inst. and State Univ., Blacksburg (USA). Dept. of Engineering Science and Mechanics

    1981-04-01

    In this study the effects of reduced integration, mesh size, and element type (i.e. linear or quadratic) on the accuracy of a penalty-finite element based on the theory governing thick, laminated, anisotropic composite plates are investigated. In order to assess the accuracy of the present finite element, exact closed-form solutions are developed for cross-ply and antisymmetric angle-ply rectangular plates simply supported and subjected to sinusoidally distributed mechanical and/or thermal loadings, and free vibration.

  4. Elastic stability of laminated, flat and curved, long rectangular plates subjected to combined inplane loads

    Science.gov (United States)

    Viswanathan, A. V.; Tamekuni, M.; Baker, L. L.

    1974-01-01

    A method is presented to predict theoretical buckling loads of long, rectangular flat and curved laminated plates with arbitrary orientation of orthotropic axes each lamina. The plate is subjected to combined inplane normal and shear loads. Arbitrary boundary conditions may be stipulated along the longitudinal sides of the plate. In the absence of inplane shear loads and extensional-shear coupling, the analysis is also applicable to finite length plates. Numerical results are presented for curved laminated composite plates with boundary conditions and subjected to various loadings. These results indicate some of the complexities involved in the numerical solution of the analysis for general laminates. The results also show that the reduced bending stiffness approximation when applied to buckling problems could lead to considerable error in some cases and therefore must be used with caution.

  5. Thermal stresses in an orthotropic rectangular plate with a rigid ribbonlike inclusion

    International Nuclear Information System (INIS)

    Sumi, N.

    1981-01-01

    On the basis of the complex variable method for determining the stationary two-dimensional thermal stresses, the thermal stresses in an orthotropic rectangular plate with a rigid ribbonlike inclusion under a steady state temperature field is considered. The solution is found by the analytic continuation argument and the modified mapping-collocation technique. Numerical results indicate a dependence of the orthotropic stress intensity factors on the thermal, elastic and geometrical constants over a certain parameter range. (orig.)

  6. Experimental and Numerical Investigation of Forced Convection Heat Transfer in Heat Sink with Rectangular Plates at Varying Inclinations on Vertical Base

    Science.gov (United States)

    Patil, Harshal Bhauso; Dingare, Sunil Vishnu

    2018-03-01

    Heat exchange upgrade is a vital territory of research area. Utilization of reasonable systems can bring about noteworthy specialized points of interest coming about reserve funds of cost. Rectangular plates are viewed as best balance arrangement utilized for heat exchange improvement. This gives an enlargement strategy to heat exchange with beginning of limit layer and vortex development. To assess and look at the rate of heat exchange enhancement by rectangular plate fins with differing inclinations (0°-30°-60°), shifting Re and heat supply under forced convection are the principle destinations of this study. The study is done by fluctuating introductions of fins with various inclinations, input heat supply and Re under forced convection. The coefficient of heat transfer increments observed with the expansion in air speed for all the examined designs. The coefficient of the heat transfer is discovered higher at the edge of introduction of fins at 30° for inline arrangement and 0° for staggered arrangement. Looking at both the arrangements, it is discovered that the heat transfer coefficient in 0° fin staggered arrangement is about 17% higher than 30° inline arrangement and 76% higher than the vertical plate fin. For plate fin heat sink, boundary layer formation and growth results in decrease of the coefficient of heat transfer in forced convection. This issue is overcome by accommodating some rectangular fins on the plate fin. It brings about increment of heat transfer coefficient of the RPFHS under the states of trial factors. As indicated by past research, it is discovered that examination of the plate fin heat sink with various sorts of fins for horizontal orientation is done yet but this investigation expects to discover the upgrade of transfer coefficient of plate fin heat sink for its vertical position with rectangular plates at different inclinations under the shifting scopes of heat input supply, fin arrangements and Reynolds number (Re).

  7. Vibration Analysis of a Magnetoelectroelastic Rectangular Plate Based on a Higher-Order Shear Deformation Theory

    Directory of Open Access Journals (Sweden)

    Alireza Shooshtari

    Full Text Available Abstract Free vibration of a magnetoelectroelastic rectangular plate is investigated based on the Reddy's third-order shear deformation theory. The plate rests on an elastic foundation and it is considered to have different boundary conditions. Gauss's laws for electrostatics and magnetostatics are used to model the electric and magnetic behavior. The partial differential equations of motion are reduced to a single partial differential equation and then by using the Galerkin method, the ordinary differential equation of motion as well as an analytical relation for the natural frequency of the plate is obtained. Some numerical examples are presented to validate the proposed model and to investigate the effects of several parameters on the vibration frequency of the considered smart plate.

  8. Topological material layout in plates for vibration suppression and wave propagation control

    DEFF Research Database (Denmark)

    Larsen, Anders Astrup; Laksafoss, B.; Jensen, Jakob Søndergaard

    2009-01-01

    We propose a topological material layout method to design elastic plates with optimized properties for vibration suppression and guided transport of vibration energy. The gradient-based optimization algorithm is based on a finite element model of the plate vibrations obtained using the Mindlin...

  9. Performance evaluation of a natural-convection solar air-heater with a rectangular-finned absorber plate

    International Nuclear Information System (INIS)

    Fakoor Pakdaman, M.; Lashkari, A.; Basirat Tabrizi, H.; Hosseini, R.

    2011-01-01

    This paper deals with an experimental investigation to evaluate different thermal characteristics of a natural-convection flat-plate solar air-heater with longitudinal rectangular fins array. Having determined the thermal performance of the system a Nusselt number correlation is presented for such finned duct devices. In the presented empirical model which may have industrial applications, solar radiation and ambient temperature have been considered as independent parameters. Other characteristics of the system such as different dimensionless variables, plates and outflow temperatures, efficiency, and mass flow rate have been empirically modeled based on these variables. The particular difference in this study in comparison with the other similar studies is the presentation of an empirical model for rectangular-finned solar air-heaters. This model proposes design concepts and rules of thumb, and demonstrates the calculations of the design parameters. Based on the order of magnitude analysis, solar radiation has been found to be the main parameter which characterizes the thermal behavior of the system. Besides, exergy analysis has been carried out, and optimum conditions in which the system has the highest performance have been determined.

  10. Exact thermal representation of multilayer rectangular structures by infinite plate structures using the method of images

    Science.gov (United States)

    Palisoc, Arthur L.; Lee, Chin C.

    1988-12-01

    Using the method of images and the analytical temperature solution to the multilayer infinite plate structure, the thermal profile over finite rectangular multilayer integrated circuit devices can be calculated exactly. The advantage of using the image method lies in the enhanced capability of arriving at an analytical solution for structures where analytical solutions do not apparently exist, e.g., circular or arbitrarily oriented rectangular sources over multilayered rectangular structures. The new approach results in large savings in computer CPU time especially for small sources over large substrates. The method also finds very important applications to integrated circuit devices with heat dissipating elements close to the edge boundaries. Results from two examples indicate that the edge boundaries of a device may also be utilized to remove heat from it. This additional heat removing capability should have important applications in high power devices.

  11. Theoretical investigation of interaction between a rectangular plate and fractional viscoelastic foundation

    Directory of Open Access Journals (Sweden)

    Chengcheng Zhang

    2014-08-01

    Full Text Available The interaction between plates and foundations is a typical problem encountered in geotechnical engineering. The long-term plate performance is highly dependent on the rheological characteristics of ground soil. Compared with conventional linear rheology, the fractional calculus-based theory is a more powerful mathematical tool that can address this issue. This paper proposes a fractional Merchant model (FMM to investigate the time-dependent behavior of a simply supported rectangular plate on viscoelastic foundation. The correspondence principle involving Laplace transforms was employed to derive the closed-form solutions of plate response under uniformly distributed load. The plate deflection, bending moment, and foundation reaction calculated using the FMM were compared with the results obtained from the analogous elastic model (EM and the standard Merchant model (SMM. It is shown that the upper and lower bound solutions of the FMM can be determined using the EM. In addition, a parametric study was performed to examine the influences of the model parameters on the time-dependent behavior of the plate–foundation interaction problem. The results indicate that a small fractional differential order corresponds to a plate resting on a sandy soil foundation, while the fractional differential order value should be increased for a clayey soil foundation. The long-term performance of a foundation plate can be accurately simulated by varying the values of the fractional differential order and the viscosity coefficient. The observations from this study reveal that the proposed fractional model has the capability to capture the variation of plate deflection over many decades of time.

  12. Vibration and Acoustic Response of Rectangular Sandwich Plate under Thermal Environment

    Directory of Open Access Journals (Sweden)

    Yuan Liu

    2013-01-01

    Full Text Available In this paper, we focus on the vibration and acoustic response of a rectangular sandwich plate which is subjected to a concentrated harmonic force under thermal environment. The critical buckling temperature is obtained to decide the thermal load. The natural frequencies and modes as well as dynamic responses are acquired by using the analytical formulations based on equivalent non-classical theory, in which the effects of shear deformation and rotational inertia are taken into account. The rise of thermal load decreases the natural frequencies and moves response peaks to the low-frequency range. The specific features of sandwich plates with different formations are discussed subsequently. As the thickness ratio of facing to core increases, the natural frequencies are enlarged, and the response peaks float to the high-frequency region. Raising the Young's modulus of the core can cause the similar trends. The accuracy of the theoretical method is verified by comparing its results with those computed by the FEM/BEM.

  13. An analysis of hot plate initial temperature effect on rectangular narrow gap quenching process

    International Nuclear Information System (INIS)

    M-Hadi Kusuma; Mulya Juarsa; Anhar Riza Antariksawan; Nandy Putra

    2012-01-01

    The understanding about thermal management in the event of a severe accident such as the melting nuclear reactor fuel and reactor core, became a priority to maintain the integrity of reactor pressure vessel. Thus the debris will not out from the reactor pressure vessel and resulting impact of more substantial to the environment. One way to maintain the integrity of the reactor pressure vessel was cooling of the excess heat generated due to the accident. To get understanding of this aspect, there search focused on the effect of the initial temperature of the hot plate in the rectangular narrow gap quenching process. The initial temperature effect on quenching process is related to cooling process (thermal management) when the occurrence of a nuclear accident due to loss of coolant accident or severe accident. In order to address the problem, it is crucial to conduct research to get a better understanding of thermal management regarding to nuclear cooling accident. The research focused on determining the rewetting temperature of hot plate cooling on 220°C, 400°C, and 600°C with 0.2 liters/sec cooling water flowrate. Experiments were carried out by injecting 85°C cooling water temperature into the narrow gap at flowrates of 0.2 liters/sec. Data of transient temperature measurements were recorded using a data acquisition system in order to know the rewetting temperature during the quenching process. This study aims to understand the effect of hot plate initial temperature on rewetting during rectangular narrow gap quenching process. The results obtained show that the rewetting point on cooling the hot plate 220°C, 400°C and 600°occurs at varying rewetting temperatures. At 220°C hot plate initial temperature, the rewetting temperature occurs on 220°C. At 400°C hot plate initial temperature, the rewetting temperature occurs on 379.51°C. At 600°C hot plate initial temperature, the rewetting temperature occurs on 426.63°C. Significant differences of hot plate

  14. Solution of the two- dimensional heat equation for a rectangular plate

    Directory of Open Access Journals (Sweden)

    Nurcan BAYKUŞ SAVAŞANERİL

    2015-11-01

    Full Text Available Laplace equation is a fundamental equation of applied mathematics. Important phenomena in engineering and physics, such as steady-state temperature distribution, electrostatic potential and fluid flow, are modeled by means of this equation. The Laplace equation which satisfies boundary values is known as the Dirichlet problem. The solutions to the Dirichlet problem form one of the most celebrated topics in the area of applied mathematics. In this study, a novel method is presented for the solution of two-dimensional heat equation for a rectangular plate. In this alternative method, the solution function of the problem is based on the Green function, and therefore on elliptic functions.

  15. Research on mechanism of the large-amplitude and narrow-band vibration of a flexible flat plate in the rectangular channel

    Energy Technology Data Exchange (ETDEWEB)

    Liu Lifang, E-mail: liu_lifang1106@yahoo.cn [School of Nuclear Science and Engineering, North China Electric Power University, Zhuxinzhuang, Dewai, Beijing 102206 (China); State Nuclear Power Software Development Center, Building 1, Compound No. 29, North Third Ring Road, Xicheng District, Beijing 100029 (China); Lu Daogang [School of Nuclear Science and Engineering, North China Electric Power University, Zhuxinzhuang, Dewai, Beijing 102206 (China)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer The large amplitude and narrow-band vibration experiment was performed. Black-Right-Pointing-Pointer The added mass theory was used to analyze the test plates' natural vibration characteristics in static water. Black-Right-Pointing-Pointer The occurring condition of the large amplitude and narrow band vibration was investigated. Black-Right-Pointing-Pointer The large amplitude and narrow-band vibration mechanism was investigated. - Abstract: Further experiments and theoretical analysis were performed to investigate mechanism of the large-amplitude and narrow-band vibration behavior of a flexible flat plate in a rectangular channel. Test plates with different thicknesses were adopted in the FIV experiments. The natural vibration characteristics of the flexible flat plates in air were tested, and the added mass theory of column was used to analyze the flexible flat plates' natural vibration characteristics in static water. It was found that the natural vibration frequency of a certain test plate in static water is approximately within the main vibration frequency band of the plate when it was induced to vibrate with the large-amplitude and narrow-band in the rectangular channel. It can be concluded that the harmonic between the flowing fluid and the vibrating plate is one of the key reasons to induce the large-amplitude and narrow-band vibration phenomenon. The occurring condition of the phenomenon and some important narrow-band vibration characteristics of a foursquare fix-supported flexible flat plate were investigated.

  16. Topology optimization for elastic base under rectangular plate subjected to moving load

    Directory of Open Access Journals (Sweden)

    Jilavyan Samvel H.

    2015-09-01

    Full Text Available Distribution optimization of elastic material under elastic isotropic rectangular thin plate subjected to concentrated moving load is investigated in the present paper. The aim of optimization is to damp its vibrations in finite (fixed time. Accepting Kirchhoff hypothesis with respect to the plate and Winkler hypothesis with respect to the base, the mathematical model of the problem is constructed as two-dimensional bilinear equation, i.e. linear in state and control function. The maximal quantity of the base material is taken as optimality criterion to be minimized. The Fourier distributional transform and the Bubnov-Galerkin procedures are used to reduce the problem to integral equality type constraints. The explicit solution in terms of two- dimensional Heaviside‘s function is obtained, describing piecewise-continuous distribution of the material. The determination of the switching points is reduced to a problem of nonlinear programming. Data from numerical analysis are presented.

  17. Maximizing band gaps in plate structures

    DEFF Research Database (Denmark)

    Halkjær, Søren; Sigmund, Ole; Jensen, Jakob Søndergaard

    2006-01-01

    periodic plate using Bloch theory, which conveniently reduces the maximization problem to that of a single base cell. Secondly, we construct a finite periodic plate using a number of the optimized base cells in a postprocessed version. The dynamic properties of the finite plate are investigated......Band gaps, i.e., frequency ranges in which waves cannot propagate, can be found in elastic structures for which there is a certain periodic modulation of the material properties or structure. In this paper, we maximize the band gap size for bending waves in a Mindlin plate. We analyze an infinite...... theoretically and experimentally and the issue of finite size effects is addressed....

  18. A Green's function solution for a rectangular heat source on an infinite plate

    International Nuclear Information System (INIS)

    Bainbridge, B.L.

    1989-01-01

    The applications associated with a rectangular heat source on an infinite plate range from integrated circuits to thin film heat flux sensors on thin substrates. The particular problem from which the solution is developed concerns the use of a resistive strip for monitoring currents generated in circuits exposed to electromagnetic fields. The Green's function formulation is solved by using early and late time approximations for which analytical solutions can be derived. In this paper expressions are developed for three sets of boundary conditions and compared to the experimental performance of a physical device

  19. Analysis of a rectangular ceramic plate in electrically forced thickness-twist vibration as a piezoelectric transformer.

    Science.gov (United States)

    Yang, Jiashi; Liu, Jinjin; Li, Jiangyu

    2007-04-01

    A rectangular ceramic plate with appropriate electrical load and operating mode is analyzed for piezoelectric transformer application. An exact solution from the three-dimensional equations of linear piezoelectricity is obtained. The solution simulates the real operating situation of a transformer as a vibrating piezoelectric body connected to a circuit. Transforming ratio, input admittance, and efficiency of the transformer are obtained.

  20. Critical heat flux analysis on change of plate temperature and cooling water flow rate for rectangular narrow gap with bilateral-heated cases

    International Nuclear Information System (INIS)

    M Hadi Kusuma; Mulya Juarsa; Anhar Riza Antariksawan

    2013-01-01

    Boiling heat transfer phenomena on rectangular narrow gap was related to the safety of nuclear reactors. Research done in order to study the safety of nuclear reactors in particular relating to boiling heat transfer and useful on the improvement of next-generation reactor designs. The research focused on calculation of the heat flux during the cooling process in rectangular narrow gap size 1.0 mm. with initial temperatures 200°C. 400°C, and 600°C, also the flow rates of cooling water 0,1 liters/second. 0,2 liters/second. and 0,3 liters/second. Experiments carried out by injecting water at a certain flow rate with the water temperature 85°C. Transient temperature measurement data recorded by the data acquisition system. Transient temperature measurement data is used to calculate the flux of heat gain is then used to obtain the heat transfer coefficient. This research aimed to obtain the correlation between critical heat flux and heat transfer coefficient to changes in temperatures and water flow rates for bilaterally-heated cases on rectangular narrow gap. The results obtained for a constant cooling water flow rate, critical heat flux will increase when hot plate temperature also increased. While on a constant hot plate temperature, coefficient heat transfer will increase when cooling water flow rate also increased. Thus it can be said that the cooling water flow rate and temperature of the hot plate has a significant effect on the critical heat flux and heat transfer coefficient resulted in quenching process of vertical rectangular narrow gap with double-heated cases. (author)

  1. DYNAMIC RESPONSE OF THICK PLATES ON TWO PARAMETER ELASTIC FOUNDATION UNDER TIME VARIABLE LOADING

    OpenAIRE

    Ozgan, Korhan; Daloglu, Ayse T.

    2014-01-01

    In this paper, behavior of foundation plates with transverse shear deformation under time variable loading is presented using modified Vlasov foundation model. Finite element formulation of thick plates on elastic foundation is derived by using an 8-noded finite element based on Mindlin plate theory. Selective reduced integration technique is used to avoid shear locking problem which arises when smaller plate thickness is considered for the evaluation of the stiffness matrices. After comparis...

  2. three dimensional photoelastic investigations on thick rectangular

    African Journals Online (AJOL)

    user

    1983-09-01

    Sep 1, 1983 ... Thick rectangular plates are investigated by means of three-dimensional photoelasticity ... a thin plate theory and a higher order thick plate theory. 1. ..... number of fringes lest the accuracy of the results will be considerably.

  3. Three-Dimensional Vibration Analysis of Rectangular Thick Plates on Pasternak Foundation with Arbitrary Boundary Conditions

    Directory of Open Access Journals (Sweden)

    Huimin Liu

    2017-01-01

    Full Text Available This paper presents the first known vibration characteristic of rectangular thick plates on Pasternak foundation with arbitrary boundary conditions on the basis of the three-dimensional elasticity theory. The arbitrary boundary conditions are obtained by laying out three types of linear springs on all edges. The modified Fourier series are chosen as the basis functions of the admissible function of the thick plates to eliminate all the relevant discontinuities of the displacements and their derivatives at the edges. The exact solution is obtained based on the Rayleigh–Ritz procedure by the energy functions of the thick plate. The excellent accuracy and reliability of current solutions are demonstrated by numerical examples and comparisons with the results available in the literature. In addition, the influence of the foundation coefficients as well as the boundary restraint parameters is also analyzed, which can serve as the benchmark data for the future research technique.

  4. Vibration characteristics of functionally graded carbon nanotube reinforced composite rectangular plates on Pasternak foundation with arbitrary boundary conditions and internal line supports

    Science.gov (United States)

    Zhong, Rui; Wang, Qingshan; Tang, Jinyuan; Shuai, Cijun; Liang, Qian

    2018-02-01

    This paper presents the first known vibration characteristics of moderately thick functionally graded carbon nanotube reinforced composite rectangular plates on Pasternak foundation with arbitrary boundary conditions and internal line supports on the basis of the firstorder shear deformation theory. Different distributions of single walled carbon nanotubes (SWCNTs) along the thickness are considered. Uniform and other three kinds of functionally graded distributions of carbon nanotubes along the thickness direction of plates are studied. The solutions carried out using an enhanced Ritz method mainly include the following three points: Firstly, create the Lagrange energy function by the energy principle; Secondly, as the main innovation point, the modified Fourier series are chosen as the basic functions of the admissible functions of the plates to eliminate all the relevant discontinuities of the displacements and their derivatives at the edges; Lastly, solve the natural frequencies as well as the associated mode shapes by means of the Ritz-variational energy method. In this study, the influences of the volume fraction of CNTs, distribution type of CNTs, boundary restrain parameters, location of the internal line supports, foundation coefficients on the natural frequencies and mode shapes of the FG-CNT reinforced composite rectangular plates are presented.

  5. Application of the Modified Vlasov Model to the Free Vibration Analysis of Thick Plates Resting on Elastic Foundations

    OpenAIRE

    Ozgan, Korhan; Daloglu, Ayse T.

    2009-01-01

    The Modified Vlasov Model is applied to the free vibration analysis of thick plates resting on elastic foundations. The effects of the subsoil depth, plate dimensions and their ratio, the value of the vertical deformation parameter within the subsoil on the frequency parameters of plates on elastic foundations are investigated. A four-noded, twelve degrees of freedom quadrilateral finite element (PBQ4) is used for plate bending analysis based on Mindlin plate theory which is effectively appli...

  6. Bottom nozzle for nuclear reactor fuel assembly having an adaptor plate and a coupled filtration plate

    International Nuclear Information System (INIS)

    Verdier, M.; Mortgat, R.

    1992-01-01

    The bottom nozzle includes an adaptor plate with openings to allow the passage of water and a filtration plate with small holes. The openings in the adaptor plate are symmetrical with regard to medians and diagonals. Within each zone, some of the openings are rectangular and some may be circular. The small holes in the filtration plate coincide with the rectangular openings in the adaptor plate

  7. Directional bending wave propagation in periodically perforated plates

    DEFF Research Database (Denmark)

    Andreassen, Erik; Manktelow, Kevin; Ruzzene, Massimo

    2015-01-01

    We report on the investigation of wave propagation in a periodically perforated plate. A unit cell with double-C perforations is selected as a test article suitable to investigate two-dimensional dispersion characteristics, group velocities, and internal resonances. A numerical model, formulated...... using Mindlin plate elements, is developed to predict relevant wave characteristics such as dispersion, and group velocity variation as a function of frequency and direction of propagation. Experimental tests are conducted through a scanning laser vibrometer, which provides full wave field information...... for the design of phononic waveguides with directional and internal resonant characteristics....

  8. Interaction of weak shock waves with rectangular meshes in plate

    Directory of Open Access Journals (Sweden)

    O.A. Mikulich

    2016-09-01

    Full Text Available In mechanical engineering, building and other industries a significant part of the process includes the presence of various dynamic loads due to technological and mechanical impacts. Consideration of such load effects allows more accurate assessment of the structural elements strength or machine parts. Aim: The aim is to develop an algorithm for calculating of dynamic stress state of plates with meshes for pulse loading in the form of a weak shock wave. Materials and Methods: An integral and discrete Fourier transform were used to solve the problem. An application of Fourier transform by time allowed reducing the dynamic problem of flat deformation to the solution of a finite number of problems for the established oscillations at fixed cyclic frequency values. In the area of Fourier-images the method of boundary integral equations and the apparatus of a complex variable function theory are used to study the dynamic stress concentration. Results: Based on the developed methodology the distribution change of the dynamic circle stress over time on the edge of a rectangular hole is studied. The time sections of stress distribution fields under the influence of pulse dynamic load is constructed.

  9. Transient thermal stresses in an orthotropic rectangular plate with convective heat transfer at upper and lower surfaces

    International Nuclear Information System (INIS)

    Sugano, Yoshihiro; Nakanishi, Takanori; Ito, Masahiko; Saito, Koichi.

    1982-01-01

    Recently, anisotropic materials have been used widely for reactor core elements and fast flying objects, therefore, the problem of thermal stress in anisotropic bodies has been studied actively. In this study, the unsteady plane thermal stress in an orthotropic rectangular thin plate heated by the temperature of ambient medium was analyzed, taking the heat transfer on both surfaces into account. The influence that the anisotropy of material constants and the heat transfer on both surfaces exert on the temperature and thermal stress of the plate was examined. Moreover, in order to investigate into the effect of the aspect ratio of the plate on the temperature and thermal stress, the unsteady distributions of temperature and thermal stress in an orthotropic semi-infinite band, of which the end surfaces are heated by ambient medium, were analyzed. The numerical calculation was carried out, and the results are shown. Before, it was difficult to satisfy the boundary condition related to shearing stress, accordingly, the analysis has not been performed, but in this study, it was shown that the analysis is possible. (Kako, I.)

  10. Study on the Effect of the Impact Location and the Type of Hammer Tip on the Frequency Response Function (FRF) in Experimental Modal Analysis of Rectangular Plates

    Science.gov (United States)

    Mali, K. D.; Singru, P. M.

    2018-03-01

    In this work effect of the impact location and the type of hammer tip on the frequency response function (FRF) is studied. Experimental modal analysis of rectangular plates is carried out for this purpose by using impact hammer, accelerometer and fast Fourier transform (FFT) analyzer. It is observed that the impulse hammer hit location has, no effect on the eigenfrequency, yet a difference in amplitude of the eigenfrequencies is obtained. The effect of the hammer tip on the pulse and the force spectrum is studied for three types of tips metal, plastic and rubber. A solid rectangular plate was excited by using these tips one by one in three different tests. It is observed that for present experimental set up plastic tip excites the useful frequency range.

  11. Finite element analysis of a solar collector plate using two plate geometries

    Directory of Open Access Journals (Sweden)

    Diego Manuel Medina Carril

    2016-09-01

    Full Text Available The thermal behavior of an absorber plate in a solar collector is investigated using finite element analysis. The thermal behavior and efficiency of two absorber plate geometries are studied, using a typical solar collector with a rectangular profile as reference, and a proposed absorber plate with curved geometry. An analysis of the most important parameters involved in the design of the absorber plate was carried out, indicating that the curved geometry of the absorber plate yields an average efficiency ~25% higher than the conventional rectangular geometry. The results suggest that a curved profile made of materials such as aluminum with thermal conductivity higher than 200W/m°C, plate thickness of the order of 2-3mm and with a large density of tubes per unit area of the collector´s plate greatly benefits the thermal efficiency of the solar collector.

  12. Stress wave calculations in composite plates using the fast Fourier transform.

    Science.gov (United States)

    Moon, F. C.

    1973-01-01

    The protection of composite turbine fan blades against impact forces has prompted the study of dynamic stresses in composites due to transient loads. The mathematical model treats the laminated plate as an equivalent anisotropic material. The use of Mindlin's approximate theory of crystal plates results in five two-dimensional stress waves. Three of the waves are flexural and two involve in-plane extensional strains. The initial value problem due to a transient distributed transverse force on the plate is solved using Laplace and Fourier transforms. A fast computer program for inverting the two-dimensional Fourier transform is used. Stress contours for various stresses and times after application of load are obtained for a graphite fiber-epoxy matrix composite plate. Results indicate that the points of maximum stress travel along the fiber directions.

  13. Study Effect of Central Rectangular Perforation on the Natural Convection Heat Transfer in an Inclined Heated Flat Plate

    Directory of Open Access Journals (Sweden)

    Kadhum Audaa Jehhef

    2015-09-01

    Full Text Available Anumerical solutions is presented to investigate the effect of inclination angle (θ , perforation ratio (m and wall temperature of the plate (Tw on the heat transfer in natural convection from isothermal square flat plate up surface heated (with and without concentrated hole. The flat plate with dimensions of (128 mm length × (64 mm width has been used five with square models of the flat plate that gave a rectangular perforation of (m=0.03, 0.06, 0.13, 0.25, 0.5. The values of angle of inclination were (0o, 15o 30o 45o 60o from horizontal position and the values of wall temperature (50oC, 60 oC, 70 oC, 90 oC, 100oC. To investigate the temperature, boundary layer thickness and heat flux distributions; the numerical computation is carried out using a very efficient integral method to solve the governing equation. The results show increase in the temperature gradient with increase in the angle of inclination and the high gradient and high heat transfer coefficients located in the external edges of the plate, for both cases: with and without holed plate. There are two separation regions of heat transfer in the external edge and the internal edges. The boundary layer thickness is small in the external edge and high in the center of the plate and it decreases as the inclination angle of plate increases. Theoretical results are compared with previous result and it is found that the Nusslet numbers in the present study are higher by (22 % than that in the previous studies. And the results show good agreement in range of Raleigh number from 105 to 106.

  14. Dynamic nonlinear interaction of elastic plates on discrete supports

    International Nuclear Information System (INIS)

    Coutinho, A.L.G.A.; Landau, L.; Lima, E.C.P. de; Ebecken, N.F.F.

    1984-01-01

    A study on the dynamic nonlinear interaction of elastic plates using the finite element method is presented. The elastic plate is discretized by 4-node isoparametric Mindlin elements. The constitutive relation of the discrete supports can be any nonlinear curve given by pairs of force-displacement points. The nonlinear behaviour is represented by the overlay approach. This model also allows the simulation of a progressive decrease on the supports stiffnesses during load cycles. The dynamic nonlinear incremental movement equations are integrated by the Newmark implicit operator. Two alternatives for the incremental-iterative formulation are compared. The paper ends with a discussion of the advantages and limitations of the presented numerical models. (Author) [pt

  15. Dynamic Analysis of Thick Plates Including Deep Beams on Elastic Foundations Using Modified Vlasov Model

    Directory of Open Access Journals (Sweden)

    Korhan Ozgan

    2013-01-01

    Full Text Available Dynamic analysis of foundation plate-beam systems with transverse shear deformation is presented using modified Vlasov foundation model. Finite element formulation of the problem is derived by using an 8-node (PBQ8 finite element based on Mindlin plate theory for the plate and a 2-node Hughes element based on Timoshenko beam theory for the beam. Selective reduced integration technique is used to avoid shear locking problem for the evaluation of the stiffness matrices for both the elements. The effect of beam thickness, the aspect ratio of the plate and subsoil depth on the response of plate-beam-soil system is analyzed. Numerical examples show that the displacement, bending moments and shear forces are changed significantly by adding the beams.

  16. Dynamics of a Circular Mindlin Plate under Mechanical Loading and Elevated Temperature

    Directory of Open Access Journals (Sweden)

    Warminska Anna

    2016-01-01

    Full Text Available Dynamics of a nonlinear circular Midlin plate is studied in the paper. The mathematical model represented by partial differential equations includes nonlinear geometrical terms resulted from large displacements. The plate is subjected to mechanical and thermal loadings. The dynamics of a coupled thermo-mechanical problem is reduced from partial to ordinary differential equations. Considering the first mode reduction and uniformly distributed temperature just a single nonlinear differential equation is obtained. The bifurcation analysis shows that elevated temperature shifts the rezonanse curve and new solutions arise. Depending on initial conditions this may lead to buckling phenomenon and then relatively small oscillations around this state, symmetric periodic oscillations of large amplitude, or irregular oscillations.

  17. A Numerical Study on the Excitation of Guided Waves in Rectangular Plates Using Multiple Point Sources

    Directory of Open Access Journals (Sweden)

    Wenbo Duan

    2017-12-01

    Full Text Available Ultrasonic guided waves are widely used to inspect and monitor the structural integrity of plates and plate-like structures, such as ship hulls and large storage-tank floors. Recently, ultrasonic guided waves have also been used to remove ice and fouling from ship hulls, wind-turbine blades and aeroplane wings. In these applications, the strength of the sound source must be high for scanning a large area, or to break the bond between ice, fouling and plate substrate. More than one transducer may be used to achieve maximum sound power output. However, multiple sources can interact with each other, and form a sound field in the structure with local constructive and destructive regions. Destructive regions are weak regions and shall be avoided. When multiple transducers are used it is important that they are arranged in a particular way so that the desired wave modes can be excited to cover the whole structure. The objective of this paper is to provide a theoretical basis for generating particular wave mode patterns in finite-width rectangular plates whose length is assumed to be infinitely long with respect to its width and thickness. The wave modes have displacements in both width and thickness directions, and are thus different from the classical Lamb-type wave modes. A two-dimensional semi-analytical finite element (SAFE method was used to study dispersion characteristics and mode shapes in the plate up to ultrasonic frequencies. The modal analysis provided information on the generation of modes suitable for a particular application. The number of point sources and direction of loading for the excitation of a few representative modes was investigated. Based on the SAFE analysis, a standard finite element modelling package, Abaqus, was used to excite the designed modes in a three-dimensional plate. The generated wave patterns in Abaqus were then compared with mode shapes predicted in the SAFE model. Good agreement was observed between the

  18. Thermal vibration of a rectangular single-layered graphene sheet with quantum effects

    International Nuclear Information System (INIS)

    Wang, Lifeng; Hu, Haiyan

    2014-01-01

    The thermal vibration of a rectangular single-layered graphene sheet is investigated by using a rectangular nonlocal elastic plate model with quantum effects taken into account when the law of energy equipartition is unreliable. The relation between the temperature and the Root of Mean Squared (RMS) amplitude of vibration at any point of the rectangular single-layered graphene sheet in simply supported case is derived first from the rectangular nonlocal elastic plate model with the strain gradient of the second order taken into consideration so as to characterize the effect of microstructure of the graphene sheet. Then, the RMS amplitude of thermal vibration of a rectangular single-layered graphene sheet simply supported on an elastic foundation is derived. The study shows that the RMS amplitude of the rectangular single-layered graphene sheet predicted from the quantum theory is lower than that predicted from the law of energy equipartition. The maximal relative difference of RMS amplitude of thermal vibration appears at the sheet corners. The microstructure of the graphene sheet has a little effect on the thermal vibrations of lower modes, but exhibits an obvious effect on the thermal vibrations of higher modes. The quantum effect is more important for the thermal vibration of higher modes in the case of smaller sides and lower temperature. The relative difference of maximal RMS amplitude of thermal vibration of a rectangular single-layered graphene sheet decreases monotonically with an increase of temperature. The absolute difference of maximal RMS amplitude of thermal vibration of a rectangular single-layered graphene sheet increases slowly with the rising of Winkler foundation modulus.

  19. Bending and stretching of plates

    CERN Document Server

    Mansfield, E H; Hemp, W S

    1964-01-01

    The Bending and Stretching of Plates deals with elastic plate theory, particularly on small- and large-deflexion theory. Small-deflexion theory concerns derivation of basic equations, rectangular plates, plates of various shapes, plates whose boundaries are amenable to conformal transformation, plates with variable rigidity, and approximate methods. Large-deflexion theory includes general equations and some exact solutions, approximate methods in large-deflexion theory, asymptotic large-deflexion theories for very thin plates. Asymptotic theories covers membrane theory, tension field theory, a

  20. A novel prediction method of vibration and acoustic radiation for rectangular plate with particle dampers

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Dongqiang; Wu, Chengjun [Xi' an Jiaotong University, Xi' an (China)

    2016-03-15

    Particle damping technology is widely used in mechanical and structural systems or civil engineering to reduce vibration and suppress noise as a result of its high efficiency, simplicity and easy implementation, low cost, and energy-saving characteristic without the need for any auxiliary power equipment. Research on particle damping theory has focused on the vibration response of the particle damping structure, but the acoustic radiation of the particle damping structure is rarely investigated. Therefore, a feasible modeling method to predict the vibration response and acoustic radiation of the particle damping structure is desirable to satisfy the actual requirements in industrial practice. In this paper, a novel simulation method based on multiphase flow theory of gas particle by COMSOL multiphysics is developed to study the vibration and acoustic radiation characteristics of a cantilever rectangular plate with Particle dampers (PDs). The frequency response functions and scattered far-field sound pressure level of the plate without and with PDs under forced vibration are predicted, and the predictions agree well with the experimental results. Results demonstrate that the added PDs have a significant effect on vibration damping and noise reduction for the primary structure. The presented work in this paper shows that the theoretical work is valid, which can provide important theoretical guidance for low-noise optimization design of particle damping structure. This model also has an important reference value for the noise control of this kind of structure.

  1. Free and Forced Vibration of the Moderately Thick Laminated Composite Rectangular Plate on Various Elastic Winkler and Pasternak Foundations

    Directory of Open Access Journals (Sweden)

    Dongyan Shi

    2017-01-01

    Full Text Available An improved Fourier series method (IFSM is applied to study the free and forced vibration characteristics of the moderately thick laminated composite rectangular plates on the elastic Winkler or Pasternak foundations which have elastic uniform supports and multipoints supports. The formulation is based on the first-order shear deformation theory (FSDT and combined with artificial virtual spring technology and the plate-foundation interaction by establishing the two-parameter foundation model. Under the framework of this paper, the displacement and rotation functions are expressed as a double Fourier cosine series and two supplementary functions which have no relations to boundary conditions. The Rayleigh-Ritz technique is applied to solve all the series expansion coefficients. The accuracy of the results obtained by the present method is validated by being compared with the results of literatures and Finite Element Method (FEM. In this paper, some results are obtained by analyzing the varying parameters, such as different boundary conditions, the number of layers and points, the spring stiffness parameters, and foundation parameters, which can provide a benchmark for the future research.

  2. Numerical investigation of boiling heat transfer on hydrocarbon mixture refrigerant in vertical rectangular minichannel

    Directory of Open Access Journals (Sweden)

    Huixing Li

    2016-05-01

    Full Text Available In order to investigate the characteristics of boiling heat transfer for hydrocarbon mixture refrigerant in plate-fin heat exchanger which is used in the petrochemical industry field, a model was established on boiling heat transfer in vertical rectangular channel. The simulated results were compared with the experimental data from literature. The results show that the deviation between the simulated results and experimental data is within ±15%. Meanwhile, the characteristic of boiling heat transfer was investigated in vertical rectangular minichannel of plate-fin heat exchanger. The results show that the boiling heat transfer coefficient increases with the increase in quality and mass flux and is slightly impacted by the heat flux. This is because that the main boiling mechanism is forced convective boiling while the contribution of nucleate boiling is slight. The correlation of Liu and Winterton is in good agreement with the simulation results. The deviation between correlation calculations and simulation results is mostly less than ±15%. These results will provide some constructive instructions for the understanding of saturated boiling mechanism in a vertical rectangular minichannel and the prediction of heat transfer performance in plate-fin heat exchanger.

  3. Numerical identification of secondary buckling phenomena of elastic rectangular plate under pure bending; Tomage wo ukeru dansei kukeiban ni shojiru niji zakutsu

    Energy Technology Data Exchange (ETDEWEB)

    Nakazawa, M.; Ikeda, K. [Tohoku University, Sendai (Japan). Faculty of Engineering; Wachi, S. [NKK Corp., Tokyo (Japan); Kuranishi, S. [Kanto Gakuin University, Yokohama (Japan)

    1995-07-21

    In this paper, the secondary buckling phenomena of the elastic rectangular plate subject to the pure bending moment are investigated. The bifurcation points are classified numerically based on the determinant of tangential stiffness matrix and of its diagonal blocks obtained by means of the group-theoretic bifurcation theory. By using the sub-matrices within the whole block-diagonalized one, the informations of the instability points and equilibrium paths after bifurcation are easily obtained. The quantitative influence of the initial imperfections are investigated based on the asymptotic laws and the Monte Carlo simulations. 30 refs., 12 figs., 1 tab.

  4. Application of the Modified Vlasov Model to the Free Vibration Analysis of Thick Plates Resting on Elastic Foundations

    Directory of Open Access Journals (Sweden)

    Korhan Ozgan

    2009-01-01

    Full Text Available The Modified Vlasov Model is applied to the free vibration analysis of thick plates resting on elastic foundations. The effects of the subsoil depth, plate dimensions and their ratio, the value of the vertical deformation parameter within the subsoil on the frequency parameters of plates on elastic foundations are investigated. A four-noded, twelve degrees of freedom quadrilateral finite element (PBQ4 is used for plate bending analysis based on Mindlin plate theory which is effectively applied to the analysis of thin and thick plates when selective reduced integration technique is used. The first ten natural frequency parameters are presented in tabular and graphical forms to show the effects of the parameters considered in the study. It is concluded that the effect of the subsoil depth on the frequency parameters of the plates on elastic foundation is generally larger than that of the other parameters considered in the study.

  5. Rectangular Shell Plating Under Uniformly Distributed Hydrostatic Pressure

    Science.gov (United States)

    Neubert, M; Sommer, A

    1940-01-01

    A check of the calculation methods used by Foppl and Henky for investigating the reliability of shell plating under hydrostatic pressure has proved that the formulas yield practical results within the elastic range of the material. Foppl's approximate calculation leaves one on the safe side. It further was found on the basis of the marked ductility of the shell plating under tensile stress that the strength is from 50 to 100 percent higher in the elastic range than expected by either method.

  6. FLOW VISUALIZATION OF RECTANGULAR SLOT AIR JET IMPINGEMENT ON FLAT SURFACES

    OpenAIRE

    Satheesha V *1, B. K. Muralidhra2, Abhilash N3, C. K. Umesh4

    2018-01-01

    Jet impingement near the mid-chord of the gas turbine blade is treated as a flat plate. Experimental and numerical investigations are carried out for a single slot air jet impinging on flat surface for two different rectangular slots of dimension (3mm x 65 mm) and (5mm x 65 mm). Experimentation is done to study the flow pattern topography on the flat target plate, with varying the flow rate from 20 LPM to 50 LPM by varying the nozzle to plate distance from 9 mm to 24 mm for slot jet of 3mm an...

  7. Analysis of counter current flow limitation during the cooling process at the rectangular narrow boundary

    International Nuclear Information System (INIS)

    Nur Rahmad Yusuf

    2013-01-01

    Experimental studies to study the mechanism of boiling heat transfer in narrow rectangular channel under severe accident scenarios of TMI-2 nuclear power plant necessary for the understanding of management-related accidents. The research aims to obtain heat flux values and the critical heat flux (CHF) during the process of boiling heat transfer in narrow rectangular channel. Research methods experimentally using the HEATING-02 test section with cooling fluid is water temperature 98 °C. Experiments performed by varying the hot plate initial temperature of 100 °C, 200 °C and 300 °C with channel size 1 mm. Boiling during the cooling process was recorded by a transient temperature on the hot plate. Temperature data used to calculate the heat flux and wall temperature, the results are represented through the boiling curve. The results show that the higher plate temperature, the narrower width of the curve will be narrower and its mean that the plate surface cooling time will be slower. Results visualization is seen that the CCF occurred at the hot plate initial temperature of 100 °C, 200 °C and 300 °C with channel size 1 mm. (author)

  8. Assessment of Theories for Free Vibration Analysis of Homogeneous and Multilayered Plates

    Directory of Open Access Journals (Sweden)

    Erasmo Carrera

    2004-01-01

    Full Text Available This paper assesses classical and advanced theories for free vibrational response of homogeneous and multilayered simply supported plates. Closed form solutions are given for thick and thin geometries. Single layer and multilayered plates made of metallic, composite and piezo-electric materials, are considered. Classical theories based on Kirchhoff and Reissner-Mindlin assumptions are compared with refined theories obtained by enhancing the order of the expansion of the displacement fields in the thickness direction z. The effect of the Zig-Zag form of the displacement distribution in z as well as of the Interlaminar Continuity of transverse shear and normal stresses at the layer interface were evaluated. A number of conclusions have been drawn. These conclusions could be used as desk-bed in order to choose the most valuable theories for a given problem.

  9. Fracture analysis of one-dimensional hexagonal quasicrystals: Researches of a finite dimension rectangular plate by boundary collocation method

    Energy Technology Data Exchange (ETDEWEB)

    Jiaxing, Cheng; Dongfa, Sheng [Southwest Forestry University, Yunnan (China)

    2017-05-15

    As an important supplement and development to crystallography, the applications about quasicrystal materials have played a core role in many fields, such as manufacturing and the space industry. Due to the sensitivity of quasicrystals to defects, the research on the fracture problem of quasicrystals has attracted a great deal of attention. We present a boundary collocation method to research fracture problems for a finite dimension rectangular one-dimensional hexagonal quasicrystal plate. Because mode I and mode II problems for one- dimensional hexagonal quasicrystals are like that for the classical elastic materials, only the anti-plane problem is discussed in this paper. The correctness of the present numerical method is verified through a comparison of the present results and the existing results. And then, the size effects on stress field, stress intensity factor and energy release rate are discussed in detail. The obtained results can provide valuable references for the fracture behavior of quasicrystals.

  10. Vibration of functionally graded plate resting on viscoelastic elastic foundation subjected to moving loads

    Science.gov (United States)

    Duy Hien, Ta; Lam, Nguyen Ngoc

    2018-04-01

    The dynamics of plates subjected to a moving load must be considered by engineering mechanics and design structures. This paper deals with the dynamic responses of functionally graded (FG) rectangular plates resting on a viscoelastic foundation under moving loads. It is assumed that material properties of the plate vary continuously in the thickness direction according to the power-law. The governing equations are derived by using Hamilton’s principle, which considers the effect of the higher-order shear deformation in the plate. Transient responses of simply supported FG rectangular plates are employed by using state-space methods. Several examples are given for displacement and stresses in the plates with various structural parameters, and the effects of these parameters are discussed.

  11. Air loads on a rigid plate oscillating normal to a fixed surface

    NARCIS (Netherlands)

    Beltman, W.M.; van der Hoogt, Peter; Spiering, R.M.E.J.; Tijdeman, H.

    1997-01-01

    This paper deals with the theoretical and experimental investigation on a rigid, rectangular plate oscillating in the proximity of a fixed surface. The plate is suspended by springs. The airloads generated by the oscillating motion of the plate are determined. Due to the fact that the plate is

  12. Determination of the elastic and stiffness characteristics of cross-laminated timber plates from flexural wave velocity measurements

    Science.gov (United States)

    Santoni, Andrea; Schoenwald, Stefan; Van Damme, Bart; Fausti, Patrizio

    2017-07-01

    Cross-laminated timber (CLT) is an engineered wood with good structural properties and it is also economically competitive with the traditional building construction materials. However, due to its low volume density combined with its high stiffness, it does not provide sufficient sound insulation, thus it is necessary to develop specific acoustic treatments in order to increase the noise reduction performance. The material's mechanical properties are required as input data to perform the vibro-acoustic analyses necessary during the design process. In this paper the elastic constants of a CLT plate are derived by fitting the real component of the experimental flexural wave velocity with Mindlin's dispersion relation for thick plates, neglecting the influence of the plate's size and boundary conditions. Furthermore, its apparent elastic and stiffness properties are derived from the same set of experimental data, for the plate considered to be thin. Under this latter assumption the orthotropic behaviour of an equivalent thin CLT plate is described by using an elliptic model and verified with experimental results.

  13. Experimental study for flow regime of downward air-water two-phase flow in a vertical narrow rectangular channel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, T. H.; Yun, B. J.; Jeong, J. H. [Pusan National University, Geunjeong-gu, Busan (Korea, Republic of)

    2015-05-15

    Studies were mostly about flow in upward flow in medium size circular tube. Although there are great differences between upward and downward flow, studies on vertical upward flow are much more active than those on vertical downward flow in a channel. In addition, due to the increase of surface forces and friction pressure drop, the pattern of gas-liquid two-phase flow bounded to the gap of inside the rectangular channel is different from that in a tube. The downward flow in a rectangular channel is universally applicable to cool the plate type nuclear fuel in research reactor. The sub-channel of the plate type nuclear fuel is designed with a few millimeters. Downward air-water two-phase flow in vertical rectangular channel was experimentally observed. The depth, width, and length of the rectangular channel is 2.35 mm, 66.7 mm, and 780 mm, respectively. The test section consists of transparent acrylic plates confined within a stainless steel frame. The flow patterns of the downward flow in high liquid velocity appeared to be similar to those observed in previous studies with upward flow. In downward flow, the transition lines for bubbly-slug and slug-churn flow shift to left in the flow regime map constructed with abscissa of the superficial gas velocity and ordinate of the superficial liquid velocity. The flow patterns observed with downward flow at low liquid velocity are different from those with upward flow.

  14. Modal analysis and nonlinear characterization of an airborne power ultrasonic transducer with rectangular plate radiator.

    Science.gov (United States)

    Andrés, R R; Acosta, V M; Lucas, M; Riera, E

    2018-01-01

    Some industrial processes like particle agglomeration or food dehydration among others can be enhanced by the use of power ultrasonic technologies. These technologies are based on an airborne power ultrasonic transducer (APUT) constituted by a pre-stressed Langevin-type transducer, a mechanical amplifier and an extensive plate radiator. In order to produce the desired effects in industrial processing, the transducer has to vibrate in an extensional mode driving an extensive radiator in the desired flexural mode with high amplitude displacements. Due to the generation of these high amplitude displacements in the radiator surfaces, non-linear effects like frequency shifts, hysteresis or modal interactions, among others, may be produced in the transducer behavior. When any nonlinear effect appears, when applying power, the stability and efficiency of this ultrasonic technology decreases, and the transducer may be damaged depending on the excitation power level and the nature of the nonlinearity. In this paper, an APUT with flat rectangular radiator is presented, as the active part of an innovative system with stepped reflectors. The nonlinear behavior of the APUT has been characterized numerically and experimentally in case of the modal analysis and experimentally in the case of dynamic analysis. According to the results obtained after the experiments, no modal interactions are expected, nor do other nonlinear effects. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Experimental study of falling water limitation under counter-current flow in the vertical rectangular channel

    International Nuclear Information System (INIS)

    Usui, Tohru; Kaminaga, Masanori; Sudo, Yukio.

    1988-07-01

    Quantitative understanding of critical heat flux (CHF) in the narrow vertical rectangular channel is required for the thermo-hydroulic design and the safety analysis of research reactors in which flat-plate-type fuel is adopted. Especially, critical heat flux under low downward velocity has a close relation with falling water limitation under counter-current flow. Accordingly, CCFL (Counter-current Flow Limitation) experiments were carried out for both vertical rectangular channels and vertical circular tubes varried in their size and configuration of their cross sections, to make clear CCFL characteristics in the vertical rectangular channels. In the experiments, l/de of the rectangular channel was changed from 3.5 to 180. As the results, it was clear that different equivalent hydraulic diameter de, namely width or water gap of channel, gave different CCFL characteristics of rectangular channel. But the influence of channel length l on CCFL characteristics was not observed. Besides, a dimensionless correlation to estimate a relation between upward air velocity and downward water velocity was proposed based on the present experimental results. The difference of CCFL characteristics between rectangular channels and circular tubes was also investigated. Especially for the rectangular channels, dry-patches appearing condition was made clear as a flow-map. (author)

  16. How Knowledge Is Constructed and Exchanged in Virtual Communities of Physicians: Qualitative Study of Mindlines Online.

    Science.gov (United States)

    Wieringa, Sietse; Engebretsen, Eivind; Heggen, Kristin; Greenhalgh, Trisha

    2018-02-02

    As a response to the criticisms evidence-based practice currently faces, groups of health care researchers and guideline makers have started to call for the appraisal and inclusion of different kinds of knowledge in guideline production (other than randomized controlled trials [RCTs]) to better link with the informal knowledge used in clinical practice. In an ethnographic study, Gabbay and Le May showed that clinicians in everyday practice situations do not explicitly or consciously use guidelines. Instead, they use mindlines: collectively shared, mostly tacit knowledge that is shaped by many sources, including accumulated personal experiences, education (formal and informal), guidance, and the narratives about patients that are shared among colleagues. In this study on informal knowledge, we consider virtual networks of clinicians as representative of the mindlines in the wider medical community, as holders of knowledge, as well as catalysts of knowing. The aim of this study was to explore how informal knowledge and its creation in communities of clinicians can be characterized as opposed to the more structured knowledge produced in guideline development. This study included a qualitative study of postings on three large virtual networks for physicians in the United Kingdom, the Netherlands, and Norway, taking the topic of statins as a case study and covering more than 1400 posts. Data were analyzed thematically with reference to theories of collaborative knowledge construction and communities of practice. The dataset showed very few postings referring to, or seeking to adhere to, explicit guidance and recommendations. Participants presented many instances of individual case narratives that highlighted quantitative test results and clinical examination findings. There was an emphasis on outliers and the material, regulatory, and practical constraints on knowledge use by clinicians. Participants conveyed not-so-explicit knowledge as tacit and practical knowledge

  17. How Knowledge Is Constructed and Exchanged in Virtual Communities of Physicians: Qualitative Study of Mindlines Online

    Science.gov (United States)

    2018-01-01

    Background As a response to the criticisms evidence-based practice currently faces, groups of health care researchers and guideline makers have started to call for the appraisal and inclusion of different kinds of knowledge in guideline production (other than randomized controlled trials [RCTs]) to better link with the informal knowledge used in clinical practice. In an ethnographic study, Gabbay and Le May showed that clinicians in everyday practice situations do not explicitly or consciously use guidelines. Instead, they use mindlines: collectively shared, mostly tacit knowledge that is shaped by many sources, including accumulated personal experiences, education (formal and informal), guidance, and the narratives about patients that are shared among colleagues. In this study on informal knowledge, we consider virtual networks of clinicians as representative of the mindlines in the wider medical community, as holders of knowledge, as well as catalysts of knowing. Objective The aim of this study was to explore how informal knowledge and its creation in communities of clinicians can be characterized as opposed to the more structured knowledge produced in guideline development. Methods This study included a qualitative study of postings on three large virtual networks for physicians in the United Kingdom, the Netherlands, and Norway, taking the topic of statins as a case study and covering more than 1400 posts. Data were analyzed thematically with reference to theories of collaborative knowledge construction and communities of practice. Results The dataset showed very few postings referring to, or seeking to adhere to, explicit guidance and recommendations. Participants presented many instances of individual case narratives that highlighted quantitative test results and clinical examination findings. There was an emphasis on outliers and the material, regulatory, and practical constraints on knowledge use by clinicians. Participants conveyed not

  18. Stress analysis and evaluation of a rectangular pressure vessel

    International Nuclear Information System (INIS)

    Rezvani, M.A.; Ziada, H.H.; Shurrab, M.S.

    1992-10-01

    This study addresses structural analysis and evaluation of an abnormal rectangular pressure vessel, designed to house equipment for drilling and collecting samples from Hanford radioactive waste storage tanks. It had to be qualified according to ASME boiler and pressure vessel code, Section VIII; however, it had the cover plate bolted along the long face, a configuration not addressed by the code. Finite element method was used to calculate stresses resulting from internal pressure; these stresses were then used to evaluate and qualify the vessel. Fatigue is not a concern; thus, it can be built according to Section VIII, Division I instead of Division 2. Stress analysis was checked against the code. A stayed plate was added to stiffen the long side of the vessel

  19. Measurements of time-dependent liquid-metal magnetohydrodynamic flows in a flat rectangular duct

    International Nuclear Information System (INIS)

    Buehler, L.; Horanyi, S.

    2009-01-01

    In the helium-cooled lead lithium (HCLL) blanket, which has been chosen as a reference concept for a liquid-metal breeding blanket to be tested in ITER, the heat is removed by helium cooled plates aligned with the strong toroidal magnetic field that confines the fusion plasma. The liquid breeder lead lithium circulates through gaps of rectangular cross-section between the cooling plates to transport the generated tritium towards external extraction facilities. Under the action of the strong magnetic field, liquid metal flows in conducting rectangular ducts exhibit jet-like velocity profiles in the thin boundary layers near the side walls, which are parallel to the magnetic field like the cooling plates in HCLL blankets. The velocity in these side layers may exceed several times the mean velocity in the duct and it is known that these layers become unstable for sufficiently high Reynolds numbers. The present paper summarizes experimental results for such unstable time-dependent flows in strong magnetic fields, which have been obtained in the MEKKA liquid metal laboratory of the Forschungszentrum Karlsruhe. In particular, spatial and temporal scales of perturbation patterns are identified. The results suggest that the flow between cooling plates in a HCLL blanket is laminar and stable. The observed time-dependent flow behavior appears at larger velocities so that the present results are more relevant for applications in dual coolant concepts where high-velocity jets have been predicted along side walls.

  20. an elasticity solution for simply suported rectangular plates

    African Journals Online (AJOL)

    MIS

    1983-09-01

    Sep 1, 1983 ... σx, σy, σz. = direct stresses ξxy, ξxz, ξyz. = shear stresses εy, εy, εz. = direct strains rxy, rxz ryz. = shear strains μ. = Poisson's ratio α = rm /Pb. = nπ/2b. R = 2 ... based on Donnell's5 thick plate theory are examined. 2. BASIC EQUATIONS. The general solution of the equations of elasticity can be expressed in.

  1. Nonlinear analysis of flexible plates lying on elastic foundation

    Directory of Open Access Journals (Sweden)

    Trushin Sergey

    2017-01-01

    Full Text Available This article describes numerical procedures for analysis of flexible rectangular plates lying on elastic foundation. Computing models are based on the theory of plates with account of transverse shear deformations. The finite difference energy method of discretization is used for reducing the initial continuum problem to finite dimensional problem. Solution procedures for nonlinear problem are based on Newton-Raphson method. This theory of plates and numerical methods have been used for investigation of nonlinear behavior of flexible plates on elastic foundation with different properties.

  2. Vortex-Induced Vibrations of a Flexibly-Mounted Cyber-Physical Rectangular Plate

    Science.gov (United States)

    Onoue, Kyohei; Strom, Benjamin; Song, Arnold; Breuer, Kenneth

    2013-11-01

    We have developed a cyber-physical system to explore the vortex-induced vibration (VIV) behavior of a flat plate mounted on a virtual spring damper support. The plate is allowed to oscillate about its mid-chord and the measured angular position, velocity, and torque are used as inputs to a feedback control system that provides a restoring torque and can simulate a wide range of structural dynamic behavior. A series of experiments were carried out using different sized plates, and over a range of freestream velocities, equilibrium angles of attack, and simulated stiffness and damping. We observe a synchronization phenomenon over a wide range of parameter space, wherein the plate oscillates at moderate to large amplitude with a frequency dictated by the natural structural frequency of the system. Additionally, the existence of bistable states is reflected in the hysteretic response of the system. The cyber-physical damping extracts energy from the flow and the efficiency of this harvesting mechanism is characterized over a range of dimensionless stiffness and damping parameters. This research is funded by the Air Force Office of Scientific Research (AFOSR).

  3. Post-buckling capacity of bi-axially loaded rectangular steel plates

    DEFF Research Database (Denmark)

    Jönsson, Jeppe; Bondum, T. H.

    2012-01-01

    slenderness and edge displacement ratio are included in the investigations presented. Capacity interaction curves are established in the bi-axial stress domain. It turns out that for certain stress ratios the imperfections dominating the ultimate capacity are not affine to the lowest classical buckling mode...... for biaxial stress. It is of great interest that short wave imperfections of a lower magnitude compared to conventionally used imperfections are seen to lower the capacity of the bi-axially loaded plates. The topic is of major concern in the flange plates of long span bridges with multi box girder...

  4. Performance of an inclined solar still with rectangular grooves and ridges

    International Nuclear Information System (INIS)

    Anburaj, P.; Kalidasa, Murugavel K.; Samuel Hansen, R.

    2013-01-01

    This work investigates the experimental performance of a new type inclined solar still with rectangular grooves and ridges in absorber plate. The still was fabricated and tested for various inclination angles of 25, 30 and 35 facing south with absorber plate. Performances of the still were compared with different wick materials (Black cotton cloth, Jute cloth, and Waste cotton pieces) on the absorber plate. The effect of placing porous material (Clay pot) and energy storing material (Mild steel pieces) in the grooves were studied. The results demonstrate that 30 inclination is optimum which yielded 3.77 L/day production. Compared to different wick materials, black cotton cloth helps to achieve maximum productivity of 4.21 L/day. The addition of permeable materials and energy absorbing materials also enhances the distillate output to 4.27 L/day. (authors)

  5. Large deflection analysis of laminated composite plates resting on nonlinear elastic foundations by the method of discrete singular convolution

    International Nuclear Information System (INIS)

    Baltacioglu, A.K.; Civalek, O.; Akgoez, B.; Demir, F.

    2011-01-01

    This paper presents nonlinear static analysis of a rectangular laminated composite thick plate resting on nonlinear two-parameter elastic foundation with cubic nonlinearity. The plate formulation is based on first-order shear deformation theory (FSDT). The governing equation of motion for a rectangular laminated composite thick plate is derived by using the von Karman equation. The nonlinear static deflections of laminated plates on elastic foundation are investigated using the discrete singular convolution method. The effects of foundation and geometric parameters of plates on nonlinear deflections are investigated. The validity of the present method is demonstrated by comparing the present results with those available in the literature. - Highlights: → Large deflection analysis of laminated composite plates are investigated. → As foundation, nonlinear elastic models have been used firstly. → The effects of three-parameter foundation are investigated in detail.

  6. Flow-induced plastic collapse of stacked fuel plates

    Energy Technology Data Exchange (ETDEWEB)

    Davis, D C; Scarton, H A

    1985-03-01

    Flow-induced plastic collapse of stacked fuel plate assemblies was first noted in experimental reactors such as the ORNL High Flux Reactor Assembly and the Engineering Test Reactor (ETR). The ETR assembly is a stack of 19 thin flat rectangular fuel plates separated by narrow channels through which a coolant flows to remove the heat generated by fission of the fuel within the plates. The uranium alloyed plates have been noted to buckle laterally and plastically collapse at the system design coolant flow rate of 10.7 m/s, thus restricting the coolant flow through adjacent channels. A methodology and criterion are developed for predicting the plastic collapse of ETR fuel plates. The criterion is compared to some experimental results and the Miller critical velocity theory.

  7. Thermal Effects on Vibration and Control of Piezocomposite Kirchhoff Plate Modeled by Finite Elements Method

    OpenAIRE

    Sanbi, M.; Saadani, R.; Sbai, K.; Rahmoune, M.

    2015-01-01

    Theoretical and numerical results of the modeling of a smart plate are presented for optimal active vibration control. The smart plate consists of a rectangular aluminum piezocomposite plate modeled in cantilever configuration with surface bonded thermopiezoelectric patches. The patches are symmetrically bonded on top and bottom surfaces. A generic thermopiezoelastic theory for piezocomposite plate is derived, using linear thermopiezoelastic theory and Kirchhoff assumptions. Finite element eq...

  8. Electromagnetic response of extraordinary transmission plates inspired on Babinet’s principle

    OpenAIRE

    Navarro Cía, Miguel; Beruete Díaz, Miguel; Sorolla Ayza, Mario

    2011-01-01

    This chapter is devoted to polarization effects arisen from perforated metallic plates exhibiting extraordinary transmission (ET). Setting aside the state-of-the-art of perforated metallic plates, we show that by applying Babinet’s principle, subwavelength hole arrays (SHAs) arranged in rectangular lattice can further enhance its potential polarization response. Different perspectives are brought about to describe and understand the particular behaviour of self-complementarines...

  9. Rectangular cartograms: the game

    NARCIS (Netherlands)

    Berg, de M.T.; Nijnatten, van F.S.B.; Speckmann, B.; Verbeek, K.A.B.

    2009-01-01

    Raisz [3] introduced rectangular cartograms in 1934 as a way of visualizing spatial information, such as population or economic strength, of a set of regions like countries or states. Rectangular cartograms represent geographic regions by rectangles; the positioning and adjacencies of the rectangles

  10. Nonlinear Mechanics of MEMS Rectangular Microplates under Electrostatic Actuation

    KAUST Repository

    Saghir, Shahid

    2016-12-01

    The first objective of the dissertation is to develop a suitable reduced order model capable of investigating the nonlinear mechanical behavior of von-Karman plates under electrostatic actuation. The second objective is to investigate the nonlinear static and dynamic behavior of rectangular microplates under small and large actuating forces. In the first part, we present and compare various approaches to develop reduced order models for the nonlinear von-Karman rectangular microplates actuated by nonlinear electrostatic forces. The reduced-order models aim to investigate the static and dynamic behavior of the plate under small and large actuation forces. A fully clamped microplate is considered. Different types of basis functions are used in conjunction with the Galerkin method to discretize the governing equations. First we investigate the convergence with the number of modes retained in the model. Then for validation purpose, a comparison of the static results is made with the results calculated by a nonlinear finite element model. The linear eigenvalue problem for the plate under the electrostatic force is solved for a wide range of voltages up to pull-in. In the second part, we present an investigation of the static and dynamic behavior of a fully clamped microplate. We investigate the effect of different non-dimensional design parameters on the static response. The forced-vibration response of the plate is then investigated when the plate is excited by a harmonic AC load superimposed to a DC load. The dynamic behavior is examined near the primary and secondary (superharmonic and subharmonic) resonances. The microplate shows a strong hardening behavior due to the cubic nonlinearity of midplane stretching. However, the behavior switches to softening as the DC load is increased. Next, near-square plates are studied to understand the effect of geometric imperfections of microplates. In the final part of the dissertation, we investigate the mechanical behavior of

  11. Acoustic plane waves normally incident on a clamped panel in a rectangular duct. [to explain noise reduction curves for reducing interior noise in aircraft

    Science.gov (United States)

    Unz, H.; Roskam, J.

    1979-01-01

    The theory of acoustic plane wave normally incident on a clamped panel in a rectangular duct is developed. The coupling theory between the elastic vibrations of the panel (plate) and the acoustic wave propagation in infinite space and in the rectangular duct is considered. The partial differential equation which governs the vibration of the panel (plate) is modified by adding to its stiffness (spring) forces and damping forces, and the fundamental resonance frequency and the attenuation factor are discussed. The noise reduction expression based on the theory is found to agree well with the corresponding experimental data of a sample aluminum panel in the mass controlled region, the damping controlled region, and the stiffness controlled region. All the frequency positions of the upward and downward resonance spikes in the sample experimental data are identified theoretically as resulting from four cross interacting major resonance phenomena: the cavity resonance, the acoustic resonance, the plate resonance, and the wooden back panel resonance.

  12. Environmental Effects on Flutter Characteristics of Laminated Composite Rectangular and Skew Panels

    Directory of Open Access Journals (Sweden)

    T.V.R. Chowdary

    1996-01-01

    Full Text Available A finite element method is presented for predicting the flutter response of laminated composite panels subjected to moisture concentration and temperature. The analysis accounts for material properties at elevated temperature and moisture concentration. The analysis is based on the first-order approximation to the linear piston theory and laminated plate theory that includes shear deformation. Both rectangular and skew panels are considered. Stability boundaries at moisture concentrations and temperatures for various lamination schemes and boundary conditions are discussed.

  13. Application of generalized function to dynamic analysis of thick plates

    International Nuclear Information System (INIS)

    Zheng, D.; Weng, Z.

    1987-01-01

    The structures with thick plates have been used extensively in national defence, mechanical engineering, chemical engineering, nuclear engineering, civil engineering, etc.. Various theories have been established to deal with the problems of elastic plates, which include the classical theory of thin plates, the improved theory of thick plates, three-dimensional elastical theory. In this paper, the derivative of δ-function is handled by using the generalized function. The dynamic analysis of thick plates subjected the concentrated load is presented. The improved Donnell's equation of thick plates is deduced and employed as the basic equation. The generalized coordinates are solved by using the method of MWR. The general expressions for the dynamic response of elastic thick plates subjected the concentrated load are given. The numerical results for rectangular plates are given herein. The results are compared with those obtained from the improved theory and the classical theory of plates. (orig./GL)

  14. Experimental investigation of onset of nucleate boiling in this rectangular channels

    International Nuclear Information System (INIS)

    Belhadj, M.; Christensen, R.N.; Aldemir, T.

    1988-01-01

    The 10 kW, HEU fueled Ohio State University Research Reactor (OSURR) will be upgraded to operate with plate type LEU U 3 Si 2 , fuel elements in the power range 250-500 kW. The core will be cooled by natural convection and an onset of nucleate boiling (ONB) margin of 1.2 will be maintained in the hot channel under steady-state operation. The validity of the correlations used for predicting ONB in plate type research reactors is not known for low heat flux-low velocity flows. An experiment has been set up at The Ohio State University to investigate ONB for laminar flow in this rectangular channels. The results show that: The Bergles-Rohsenow correlation and the correlation proposed by Ricque and Siboul predict higher and lower ONB fluxes than actual, respectively. The ONB heat flux is flow velocity dependent

  15. Multi-axis force sensing using a resonant composite piezoelectric plate: model and experiments

    Science.gov (United States)

    Castaño-Cano, Davinson; Grossard, Mathieu; Hubert, Arnaud

    2015-05-01

    Wrist force/torque sensors used in robotic applications increase the performances and flexibility of the automated tasks. They also offer new possibilities in the manufacturing process, where physical contact between the work-piece and environment is required. The wide spreading of these sensors is for now restricted by their features. As an alternative to the existing strain-gauges force sensors, this paper presents a resonant composite structure, which is sensitive to multiple components of force that are considered via the pre-stress effect. Structurally bonded piezoelectric patches are used to bring the structure to its resonance, which is shifted according to applied forces. The relationship between force and frequency shift is modelled considering the multi-physics of this smart structure. This model is built using Hamilton's principle and takes into account pre-stress phenomena. A finite element model (FEM) based on Mindlin theory for plates, has been derived from the analytical model. The FEM model is implemented in MATLAB and compared with commercial FE software. Finally, an experimental prototype validates the model, and shows that it is possible to measure multiple force-components with one single sensing element such as a plate.

  16. Multi-axis force sensing using a resonant composite piezoelectric plate: model and experiments

    International Nuclear Information System (INIS)

    Castaño-Cano, Davinson; Grossard, Mathieu; Hubert, Arnaud

    2015-01-01

    Wrist force/torque sensors used in robotic applications increase the performances and flexibility of the automated tasks. They also offer new possibilities in the manufacturing process, where physical contact between the work-piece and environment is required. The wide spreading of these sensors is for now restricted by their features. As an alternative to the existing strain-gauges force sensors, this paper presents a resonant composite structure, which is sensitive to multiple components of force that are considered via the pre-stress effect. Structurally bonded piezoelectric patches are used to bring the structure to its resonance, which is shifted according to applied forces. The relationship between force and frequency shift is modelled considering the multi-physics of this smart structure. This model is built using Hamilton's principle and takes into account pre-stress phenomena. A finite element model (FEM) based on Mindlin theory for plates, has been derived from the analytical model. The FEM model is implemented in MATLAB and compared with commercial FE software. Finally, an experimental prototype validates the model, and shows that it is possible to measure multiple force-components with one single sensing element such as a plate. (paper)

  17. Experimental evaluation on natural convection heat transfer of microencapsulated phase change materials slurry in a rectangular heat storage tank

    International Nuclear Information System (INIS)

    Zhang Yanlai; Rao Zhonghao; Wang Shuangfeng; Zhang Zhao; Li Xiuping

    2012-01-01

    Highlights: ► It gives heat transfer characteristics in a rectangular heat storage tank as the basic unit for reservoir of thermal storage. ► Onset of natural convection gets easier for the MPCMS with a higher mass concentration. ► It enhances the heat transfer ability of natural convection for the MPCMS. ► Obtained the relationship between Ra and Nu of the MPCMS. - Abstract: The main purpose of this experiment is to evaluate natural convection heat transfer characteristics of microencapsulated PCM (phase change material) slurry (MPCMS) during phase change process in a rectangular heat storage tank heated from the bottom and cooled at the top. The microencapsulated PCM is several material compositions of n-paraffin waxes (mainly nonadecane) as the core materials, outside a layer of a melamine resin wrapped. In the present study, its slurry is used mixing with water. And the specific heat capacity with latent heat shows a peak value at the temperature of about T = 31 °C. We investigate the influences of the phase change process of the MPCMS on natural convection heat transfer. The experimental results indicate that phase change process of the MPCMS promote natural convection heat transfer. The local maximum heat transfer enhancement occurs at approximately T H = 34 °C corresponding to the heated plate temperature. With high mass concentration C m , the onset of natural convection gets easier for the MPCMS. The temperature gradient is larger near top plate and bottom plate of a rectangular heat storage tank. Heat transfer coefficient increases with the phase change of the PCM. And it summarizes that the phase change process of the PCM promote the occurrence of natural convection.

  18. Flexural Strength of Carbon Fiber Reinforced Polymer Repaired Cracked Rectangular Hollow Section Steel Beams

    Directory of Open Access Journals (Sweden)

    Tao Chen

    2015-01-01

    Full Text Available The flexural behavior of rectangular hollow section (RHS steel beams with initial crack strengthened externally with carbon fiber reinforced polymer (CFRP plates was studied. Eight specimens were tested under three-point loading to failure. The experimental program included three beams as control specimens and five beams strengthened with CFRP plates with or without prestressing. The load deflection curves were graphed and failure patterns were observed. The yield loads and ultimate loads with or without repairing were compared together with the strain distributions of the CFRP plate. It was concluded that yield loads of cracked beams could be enhanced with repairing. Meanwhile, the ultimate loads were increased to some extent. The effect of repair became significant with the increase of the initial crack depth. The failure patterns of the repaired specimens were similar to those of the control ones. Mechanical clamping at the CFRP plate ends was necessary to avoid premature peeling between the CFRP plate and the steel beam. The stress levels in CFRP plates were relatively low during the tests. The use of prestressing could improve the utilization efficiency of CFRP plates. It could be concluded that the patching repair could be used to restore the load bearing capacity of the deficient steel beams.

  19. Numerical investigation of boiling heat transfer on hydrocarbon mixture refrigerant in vertical rectangular minichannel

    OpenAIRE

    Huixing Li; Yu Liu

    2016-01-01

    In order to investigate the characteristics of boiling heat transfer for hydrocarbon mixture refrigerant in plate-fin heat exchanger which is used in the petrochemical industry field, a model was established on boiling heat transfer in vertical rectangular channel. The simulated results were compared with the experimental data from literature. The results show that the deviation between the simulated results and experimental data is within ±15%. Meanwhile, the characteristic of boiling heat t...

  20. Review of Critical Heat Flux Correlations for Upward Flow in a Vertical Thin Rectangular Channel

    International Nuclear Information System (INIS)

    Choi, Gil Sik; Chang, Soon Heung

    2014-01-01

    From the view point of safety, this type of fuel has higher resistance to earthquake and external impact. The cross section of coolant flow channel in the reactor core composed with the plate fuel is a thin rectangular shape. Thermal-hydraulic characteristics of this thin rectangular channel are different with those of general circular rod fuel bundle flow channel. Accordingly it could be thought that the CHF correlation in a thin rectangular channel is different with that in a circular channel, for which a large number of researches on CHF prediction have been carried out. The objective of this paper is to review previous researches on CHF in a thin rectangular channel, summarize the important conclusion and propose the new simple CHF correlation, which is based on the data set under high pressure and high flow rate condition. The researches on CHF in rectangular channel have been partially carried out according to the pressure, heated surface number, heated surface wettability effect, flow driving force and flow direction conditions. From the literature researches on CHF for upward flow in a vertical thin rectangular channel, some CHF prediction methods were reviewed and compared. There is no universal correlation which can predict CHF at all conditions, but generally, Katto empirical correlation is known to be useful at high pressure and high flow rate. The new simple correlation was developed from the restricted data set, the CHF prediction capacity of which is better than that of Katto. Even though the prediction consistency of the new simple correlation is lower, MAE and RMS error decreased quite. For the more development of the new simple CHF correlation, the more advanced regression analysis method and theoretical analysis should be studied in future

  1. Review of Critical Heat Flux Correlations for Upward Flow in a Vertical Thin Rectangular Channel

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Gil Sik; Chang, Soon Heung [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2014-05-15

    From the view point of safety, this type of fuel has higher resistance to earthquake and external impact. The cross section of coolant flow channel in the reactor core composed with the plate fuel is a thin rectangular shape. Thermal-hydraulic characteristics of this thin rectangular channel are different with those of general circular rod fuel bundle flow channel. Accordingly it could be thought that the CHF correlation in a thin rectangular channel is different with that in a circular channel, for which a large number of researches on CHF prediction have been carried out. The objective of this paper is to review previous researches on CHF in a thin rectangular channel, summarize the important conclusion and propose the new simple CHF correlation, which is based on the data set under high pressure and high flow rate condition. The researches on CHF in rectangular channel have been partially carried out according to the pressure, heated surface number, heated surface wettability effect, flow driving force and flow direction conditions. From the literature researches on CHF for upward flow in a vertical thin rectangular channel, some CHF prediction methods were reviewed and compared. There is no universal correlation which can predict CHF at all conditions, but generally, Katto empirical correlation is known to be useful at high pressure and high flow rate. The new simple correlation was developed from the restricted data set, the CHF prediction capacity of which is better than that of Katto. Even though the prediction consistency of the new simple correlation is lower, MAE and RMS error decreased quite. For the more development of the new simple CHF correlation, the more advanced regression analysis method and theoretical analysis should be studied in future.

  2. The baffle influence on sound radiation characteristics of a plate

    Directory of Open Access Journals (Sweden)

    Bao Liu

    2017-01-01

    Full Text Available The acoustic radiation characteristics of the baffle plates and unbaffle plates are calculated and compared by single-layer potential and double-layer potential. Based on the boundary integral equation, the sound pressure integral equation of the baffle and the baffle are deduced respectively. According to the boundary compatibility condition, the sound pressure and the vibration velocity of the plates are obtained. Further, the dynamic equation of the structure is substituted into the vibration equation in the form of the baffle plate and the baffle plate. The sound pressure difference and the displacement of a plate surface are in the form of the vibration mode superposition and the acoustic radiation impedance of the double integral form is obtained, which determines vibration mode coefficient and sound radiation parameters. The effect of the baffle on the acoustic radiation characteristics of the thin plate is analyzed by comparing the acoustic radiation parameters with the simple and simple rectangular plate in water.

  3. Static and Monoharmonic Acoustic Impact on a Laminated Plate

    Science.gov (United States)

    Paimushin, V. N.; Gazizullin, R. K.

    2017-07-01

    A discrete layered damping model of a multilayer plate at small displacements and deformations, with account of the internal damping of layers according to the Thompson-Kelvin-Voight model, is presented. Based on the equations derived, an analytical solution to the static deformation problem for single-layer rectangular plate hinge-supported along its contour and subjected of a uniformly distributed pressure applied to one of its boundary planes is obtained. Its convergence to the three-dimensional solution is analyzed in relation to the dimension of mesh in the thickness direction of the plate. It is found that, for thin plates, the dimension of the problem formulated can be reduced on the basis of simplified hypotheses applied to each layer. An analytical solutions is also constructed for the forced vibrations of two- and three-layer rectangular plates hinged in the opening of an absolutely stiff dividing wall upon transmission of a monoharmonic sound wave through them. It was assumed that the dividing wall is situated between two absolutely stiff barriers; one of them, owing to the harmonic vibration with a given displacement amplitude of the plate, forms an incident sound wave, and the other is stationary and is coated by a energy-absorbing material with high damping properties. Behavior of the acoustic media in spaces between the deformable plate and the barriers is described by the classical wave equations based on the model of an ideal compressible fluid. To describe the process of dynamic deformation of the energy-absorbing coating of the fixed barrier, two-dimensional equations of motion are derived based on the model of a transversely soft layer, a linear approximation of displacement fields in the thickness direction of the coating, and the account of damping properties of its material by using the hysteresis model. The effect of physical and mechanical parameters of the mechanical system considered and of frequency of the incident sound wave on the

  4. Analytical results for post-buckling behaviour of plates in compression and in shear

    Science.gov (United States)

    Stein, M.

    1985-01-01

    The postbuckling behavior of long rectangular isotropic and orthotropic plates is determined. By assuming trigonometric functions in one direction, the nonlinear partial differential equations of von Karman large deflection plate theory are converted into nonlinear ordinary differential equations. The ordinary differential equations are solved numerically using an available boundary value problem solver which makes use of Newton's method. Results for longitudinal compression show different postbuckling behavior between isotropic and orthotropic plates. Results for shear show that change in inplane edge constraints can cause large change in postbuckling stiffness.

  5. Partitioning sparse rectangular matrices for parallel processing

    Energy Technology Data Exchange (ETDEWEB)

    Kolda, T.G.

    1998-05-01

    The authors are interested in partitioning sparse rectangular matrices for parallel processing. The partitioning problem has been well-studied in the square symmetric case, but the rectangular problem has received very little attention. They will formalize the rectangular matrix partitioning problem and discuss several methods for solving it. They will extend the spectral partitioning method for symmetric matrices to the rectangular case and compare this method to three new methods -- the alternating partitioning method and two hybrid methods. The hybrid methods will be shown to be best.

  6. Partial rectangular metric spaces and fixed point theorems.

    Science.gov (United States)

    Shukla, Satish

    2014-01-01

    The purpose of this paper is to introduce the concept of partial rectangular metric spaces as a generalization of rectangular metric and partial metric spaces. Some properties of partial rectangular metric spaces and some fixed point results for quasitype contraction in partial rectangular metric spaces are proved. Some examples are given to illustrate the observed results.

  7. equilibrium approach in thederivation of differential equations

    African Journals Online (AJOL)

    user

    DEPT OF CIVIL ENGINEERING, ENUGU STATE UNIVERSITY OF SCIENCE & TECHNOLOGY ... In this paper, the differential equations of Mindlin plates are derived from basic principles by ..... Journal of Applied Mechanics, pages 31-38.

  8. High precision refractometry based on Fresnel diffraction from phase plates.

    Science.gov (United States)

    Tavassoly, M Taghi; Naraghi, Roxana Rezvani; Nahal, Arashmid; Hassani, Khosrow

    2012-05-01

    When a transparent plane-parallel plate is illuminated at a boundary region by a monochromatic parallel beam of light, Fresnel diffraction occurs because of the abrupt change in phase imposed by the finite change in refractive index at the plate boundary. The visibility of the diffraction fringes varies periodically with changes in incident angle. The visibility period depends on the plate thickness and the refractive indices of the plate and the surrounding medium. Plotting the phase change versus incident angle or counting the visibility repetition in an incident-angle interval provides, for a given plate thickness, the refractive index of the plate very accurately. It is shown here that the refractive index of a plate can be determined without knowing the plate thickness. Therefore, the technique can be utilized for measuring plate thickness with high precision. In addition, by installing a plate with known refractive index in a rectangular cell filled with a liquid and following the described procedures, the refractive index of the liquid is obtained. The technique is applied to measure the refractive indices of a glass slide, distilled water, and ethanol. The potential and merits of the technique are also discussed.

  9. Influence of the wavelet order on proper damage location in plate structures

    Science.gov (United States)

    Pawlak, Zdzisław; Knitter-Piątkowska, Anna

    2018-01-01

    The rectangular thin plates were analyzed in the paper. The static response in plate structure subjected to the uniform load was derived by applying the finite element method. In the dynamic, experimental tests the accelerations were obtained with the use of modal hammer and DEWEsoft® software. Next, the analysis of the signal was carried out with the use of Discrete Wavelet Transform (DWT), provided that damage exists in the considered plate structure. It was assumed, that in the middle of the structure a certain area of the plate is thinner or there is a crack across the entire plate thickness. The aim of this work was to choose the appropriate wavelet order to reveal the localization of defect. The results of selected numerical example proved the efficiency of proposed approach.

  10. C1-continuous Virtual Element Method for Poisson-Kirchhoff plate problem

    Energy Technology Data Exchange (ETDEWEB)

    Gyrya, Vitaliy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mourad, Hashem Mohamed [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-09-20

    We present a family of C1-continuous high-order Virtual Element Methods for Poisson-Kirchho plate bending problem. The convergence of the methods is tested on a variety of meshes including rectangular, quadrilateral, and meshes obtained by edge removal (i.e. highly irregular meshes). The convergence rates are presented for all of these tests.

  11. Vibroacoustic study of a point-constrained plate mounted in a duct

    Science.gov (United States)

    Sapkale, Swapnil L.; Sucheendran, Mahesh M.; Gupta, Shakti S.; Kanade, Shantanu V.

    2018-04-01

    The vibroacoustic study of the interaction of sound with a point-constrained, simply-supported square plate is considered in this paper. The plate is mounted flush on one of the walls of an infinite duct of rectangular cross section and is backed by a cavity. The plate response and the acoustic field is predicted by solving the coupled governing equations using modal expansion with the relevant eigenmodes of the plate dynamics and acoustic fields in the duct and cavity. By varying the location of the point constraint, the frequency characteristics of the transmission loss in the duct can be tuned. The point constraint can also alter the amplitude and spectral characteristics of the plate's response. Interestingly, some new peaks are observed in the response because of the excitation of unsymmetric modes which are otherwise dormant. Mode-localization phenomenon, which is the localization of vibration in specific regions of the plate, is observed for selected constrained points.

  12. Application of generalized function to dynamic analysis of elasto-plastic thick plates

    International Nuclear Information System (INIS)

    Zheng, D.; Weng, Z.

    1987-01-01

    The elasto-plastic dynamic analysis of thick plates is of great significance to the research and the design on an anti-seismic structure and an anti-explosive structure. In this paper, the derivative of δ-function is handled by using the generalized function. The dynamic influence coefficient of thick plates in deduced. A dynamic response of elasto-plastic thick plates its material has hardening behaviour considered, is analysed by using known elastic solutions. The general expressions for the dynamic response of elasto-plastic rectangular thick plates subjected arbitrary loads are given. Detailed computations are performed for the square plates of various height-span ratios. The results are compared with those obtained from the improved theory and the classical theory of plates. The modification of the classical deflection theory for plates is employed. The increment analysis is used for calculations. The yield function is considered as a function of inplane and transverse shear stresses. (orig./GL)

  13. Simplified description of out-of-plane waves in thin annular elastic plates

    DEFF Research Database (Denmark)

    Zadeh, Maziyar Nesari; Sorokin, Sergey

    2013-01-01

    Dispersion relations are derived for the out-of-plane wave propagation in planar elastic plates with constant curvature using the classical Kirchhoff thin plate theory. The dispersion diagrams and the mode shapes are compared with their counterparts for a straight plate strip and the role...... of curvature is assessed for plates with unconstrained edges. Elementary Bernoulli–Euler theory for a beam of rectangular cross-section with the circular shape of its axis is also employed to analyze the wave guide properties of this structure in its out-of-plane deformation. The applicability range...... of the elementary beam theory is validated. The wave finite element method in the formulation of the three-dimensional elasticity theory is used to ensure that the comparison of dispersion diagrams is performed in the frequency range, where the classical thin plate theory is valid. Thus, the paper summarizes...

  14. Microwave corrosion detection using open ended rectangular waveguide sensors

    Energy Technology Data Exchange (ETDEWEB)

    Qaddoumi, N.; Handjojo, L.; Bigelow, T.; Easter, J.; Bray, A.; Zoughi, R.

    2000-02-01

    The use of microwave and millimeter wave nondestructive testing methods utilizing open ended rectangular waveguide sensors has shown great potential for detecting minute thickness variations in laminate structures, in particular those backed by a conducting plate. Slight variations in the dielectric properties of materials may also be detected using a set of optimal parameters which include the standoff distance and the frequency of operation. In a recent investigation, on detecting rust under paint, the dielectric properties of rust were assumed to be similar to those of Fe{sub 2}O{sub 3} powder. These values were used in an electromagnetic model that simulates the interaction of fields radiated by a rectangular waveguide aperture with layered structures to obtain optimal parameters. The dielectric properties of Fe{sub 2}O{sub 3} were measured to be very similar to the properties of paint. Nevertheless, the presence of a simulated Fe{sub 2}O{sub 3} layer under a paint layer was detected. In this paper the dielectric properties of several different rust samples from different environments are measured. The measurements indicate that the nature of real rust is quite diverse and is different from Fe{sub 2}O{sub 3} and paint, indicating that the presence of rust under paint can be easily detected. The same electromagnetic model is also used (with the newly measured dielectric properties of real rust) to obtain an optimal standoff distance at a frequency of 24 GHz. The results indicate that variations in the magnitude as well as the phase of the reflection coefficient can be used to obtain information about the presence of rust. An experimental investigation on detecting the presence of very thin rust layers (2.5--5 x 10{sup {minus}2} mm [09--2.0 x 10{sup {minus}3} in.]) using an open ended rectangular waveguide probe is also conducted. Microwave images of rusted specimens, obtained at 24 GHz, are also presented.

  15. Optimizing the longitudinal and transverse electroosmotic pumping in a rectangular channel with horizontal baffle plates

    Science.gov (United States)

    Lai, Anison K. R.; Chang, Chien-Cheng; Wang, Chang-Yi

    2018-04-01

    This paper presents a continued study to our previous work on electroosmotic (EO) flow in a channel with vertical baffle plates by further investigating EO flow through an array of baffle plates arranged in parallel to the channel walls. The flow may be driven either in the direction along or in the direction transverse to the plates, thus distinguishing the longitudinal EO pumping (LEOP) and the transverse EO pumping (TEOP). In both types of EO pumping, it is more interesting to examine the cases when the baffle plates develop a higher zeta potential (denoted by α) than that on the channel walls (β). This semi-analytical study enables us to compare between LEOP and TEOP in the pumping efficiency under similar conditions. The TEOP case is more difficult to solve due to the higher order governing partial differential equations caused by the induced non-uniform pressure gradient distribution. In particular, we examine how the EO pumping rates deviate from those predicted by the Helmholtz-Smoluchowski velocity and illustrate the general trend of optimizing the EO pumping rates with respect to the physical and geometric parameters involved.

  16. Damage of plates due to impact, dynamic pressure and explosive loads

    Directory of Open Access Journals (Sweden)

    Norman Jones

    Full Text Available It is the purpose of this article to present design equations which can be used to predict the damage of ductile plating when subjected to mass impact, dynamic pressure or impulsive loadings. The external loadings are sufficiently severe to produce inelastic material behaviour and produce finite transverse displacement, or geometry change, effects. The damage is characterised as the final or permanent transverse displacement of a plate. The theoretical method predicts values for the maximum permanent transverse displacements which agree reasonably well with the corresponding experimental results generated on aluminium alloy circular, square and rectangular plates. Thus, the equations presented in this article are valuable for preliminary design purposes and for forensic studies, while the experimental data can be used for validating numerical schemes.

  17. Characterization and analysis of surface notches on Ti-alloy plates fabricated by additive manufacturing techniques

    Science.gov (United States)

    Chan, Kwai S.

    2015-12-01

    Rectangular plates of Ti-6Al-4V with extra low interstitial (ELI) were fabricated by layer-by-layer deposition techniques that included electron beam melting (EBM) and laser beam melting (LBM). The surface conditions of these plates were characterized using x-ray micro-computed tomography. The depth and radius of surface notch-like features on the LBM and EBM plates were measured from sectional images of individual virtual slices of the rectangular plates. The stress concentration factors of individual surface notches were computed and analyzed statistically to determine the appropriate distributions for the notch depth, notch radius, and stress concentration factor. These results were correlated with the fatigue life of the Ti-6Al-4V ELI alloys from an earlier investigation. A surface notch analysis was performed to assess the debit in the fatigue strength due to the surface notches. The assessment revealed that the fatigue lives of the additively manufactured plates with rough surface topographies and notch-like features are dominated by the fatigue crack growth of large cracks for both the LBM and EBM materials. The fatigue strength reduction due to the surface notches can be as large as 60%-75%. It is concluded that for better fatigue performance, the surface notches on EBM and LBM materials need to be removed by machining and the surface roughness be improved to a surface finish of about 1 μm.

  18. Characterization and analysis of surface notches on Ti-alloy plates fabricated by additive manufacturing techniques

    International Nuclear Information System (INIS)

    Chan, Kwai S.

    2015-01-01

    Rectangular plates of Ti–6Al–4V with extra low interstitial (ELI) were fabricated by layer-by-layer deposition techniques that included electron beam melting (EBM) and laser beam melting (LBM). The surface conditions of these plates were characterized using x-ray micro-computed tomography. The depth and radius of surface notch-like features on the LBM and EBM plates were measured from sectional images of individual virtual slices of the rectangular plates. The stress concentration factors of individual surface notches were computed and analyzed statistically to determine the appropriate distributions for the notch depth, notch radius, and stress concentration factor. These results were correlated with the fatigue life of the Ti–6Al–4V ELI alloys from an earlier investigation. A surface notch analysis was performed to assess the debit in the fatigue strength due to the surface notches. The assessment revealed that the fatigue lives of the additively manufactured plates with rough surface topographies and notch-like features are dominated by the fatigue crack growth of large cracks for both the LBM and EBM materials. The fatigue strength reduction due to the surface notches can be as large as 60%–75%. It is concluded that for better fatigue performance, the surface notches on EBM and LBM materials need to be removed by machining and the surface roughness be improved to a surface finish of about 1 μm. (paper)

  19. Buckling of Flat Thin Plates under Combined Loading

    Directory of Open Access Journals (Sweden)

    Ion DIMA

    2015-03-01

    Full Text Available This article aims to provide a quick methodology to determine the critical values of the forces applied to the central plane of a flat isotropic plate at which a change to the stable configuration of equilibrium occurs. Considering the variety of shapes, boundary conditions and loading combinations, the article does not intend to make an exhaustive presentation of the plate buckling. As an alternative, there will be presented only the most used configurations such as: rectangular flat thin plates, boundary conditions with simply supported (hinged or clamped (fixed edges, combined loadings with single compression or single shear or combination between them, compression and shear, with or without transverse loading, encountered at wings and control surfaces shell of fin and rudder or stabilizer and elevator. The reserve factor and the critical stresses will be calculated using comparatively two methods, namely the methodology proposed by the present article and ASSIST 6.6.2.0 – AIRBUS France software, a dedicated software to local calculations, for a simply supported plate under combined loading, compression on the both sides and shear.

  20. Rectangular-section mirror light pipes

    Energy Technology Data Exchange (ETDEWEB)

    Swift, P.D.; Lawlor, R. [School of Physical Sciences, Dublin City University, Dublin 9 (Ireland); Smith, G.B.; Gentle, A. [Department of Applied Physics, University of Technology, Sydney, Broadway, NSW 2007 (Australia)

    2008-08-15

    Using an integrated-ray approach an expression for the transmission of rectangular section mirror light pipe (MLP) has been derived for the case of collimated light input. The transmittance and the irradiance distribution at the exit aperture of rectangular-section MLPs have been measured experimentally and calculated theoretically for the case of collimated light input. The results presented extend the description of MLPs from the cylindrical case. Measured and calculated transmittances and irradiance distributions are in good agreement. (author)

  1. Obtaining S values for rectangular--solid tumors inside rectangular--solid host organs

    International Nuclear Information System (INIS)

    Stinchcomb, T.G.; Durham, J.S.; Fisher, D.R.

    1991-01-01

    A method is described for obtaining S values between a tumor and its host organ for use with the MIRD formalism. It applies the point-source specific absorbed fractions for an infinite water medium, tabulated by Berger, to a rectangular solid of arbitrary dimensions which contains a rectangular tumor of arbitrary dimensions. Contributions from pairs of source and target volume elements are summed for the S values between the tumor and itself, between the remaining healthy host organ and itself, and between the tumor and the remaining healthy host organ, with the reciprocity theorem assumed for the last. This method labeled MTUMOR, is interfaced with the widely used MIRDOSE program which incorporates the MIRD formalism. An example is calculated

  2. Dynamic analysis of isotropic nanoplates subjected to moving load using state-space method based on nonlocal second order plate theory

    Energy Technology Data Exchange (ETDEWEB)

    Nami, Mohammad Rahim [Shiraz University, Shiraz, Iran (Iran, Islamic Republic of); Janghorban, Maziar [Islamic Azad University, Marvdash (Iran, Islamic Republic of)

    2015-06-15

    In this work, dynamic analysis of rectangular nanoplates subjected to moving load is presented. In order to derive the governing equations of motion, second order plate theory is used. To capture the small scale effects, the nonlocal elasticity theory is adopted. It is assumed that the nanoplate is subjected to a moving concentrated load with the constant velocity V in the x direction. To solve the governing equations, state-space method is used to find the deflections of rectangular nanoplate under moving load. The results obtained here reveal that the nonlocality has significant effect on the deflection of rectangular nanoplate subjected to moving load.

  3. Rectangular maximum-volume submatrices and their applications

    KAUST Repository

    Mikhalev, Aleksandr; Oseledets, I.V.

    2017-01-01

    We introduce a definition of the volume of a general rectangular matrix, which is equivalent to an absolute value of the determinant for square matrices. We generalize results of square maximum-volume submatrices to the rectangular case, show a connection of the rectangular volume with an optimal experimental design and provide estimates for a growth of coefficients and an approximation error in spectral and Chebyshev norms. Three promising applications of such submatrices are presented: recommender systems, finding maximal elements in low-rank matrices and preconditioning of overdetermined linear systems. The code is available online.

  4. Rectangular maximum-volume submatrices and their applications

    KAUST Repository

    Mikhalev, Aleksandr

    2017-10-18

    We introduce a definition of the volume of a general rectangular matrix, which is equivalent to an absolute value of the determinant for square matrices. We generalize results of square maximum-volume submatrices to the rectangular case, show a connection of the rectangular volume with an optimal experimental design and provide estimates for a growth of coefficients and an approximation error in spectral and Chebyshev norms. Three promising applications of such submatrices are presented: recommender systems, finding maximal elements in low-rank matrices and preconditioning of overdetermined linear systems. The code is available online.

  5. Visualization experimental investigation on long stripe coherent structure in small-scale rectangular channel

    International Nuclear Information System (INIS)

    Su Jiqiang; Sun Zhongning; Fan Guangming; Wang Shiming

    2013-01-01

    The long stripe coherent structure of the turbulent boundary layer in a small- scale vertical rectangular channel was observed by using hydrogen bubble flow trace visualization technique. The statistical properties of the long stripe in the experimental channel boundary layer were compared with that in the smooth flat plate boundary layer. The pitch characteristics were explained by the formation mechanism of the long stripe. It was analyzed that how the change of y + affected the distribution of the long stripe. In addition, the frequency characteristics of the long stripe were also investigated, and the correlation of the long stripe frequency in such a flow channel was obtained. (authors)

  6. Best connected rectangular arrangements

    Directory of Open Access Journals (Sweden)

    Krishnendra Shekhawat

    2016-03-01

    Full Text Available It can be found quite often in the literature that many well-known architects have employed either the golden rectangle or the Fibonacci rectangle in their works. On contrary, it is rare to find any specific reason for using them so often. Recently, Shekhawat (2015 proved that the golden rectangle and the Fibonacci rectangle are one of the best connected rectangular arrangements and this may be one of the reasons for their high presence in architectural designs. In this work we present an algorithm that generates n-4 best connected rectangular arrangements so that the proposed solutions can be further used by architects for their designs.

  7. Use of rectangular grid miniplates for fracture fixation at the mandibular angle.

    Science.gov (United States)

    Hochuli-Vieira, Eduardo; Ha, Thi Khanh Linh; Pereira-Filho, Valfrido Antonio; Landes, Constantin Alexander

    2011-05-01

    The aim of this study was to evaluate the clinical outcome of patients with mandibular angle fractures treated by intraoral access and a rectangular grid miniplate with 4 holes and stabilized with monocortical screws. This study included 45 patients with mandibular angle fractures from the Department of Oral and Maxillofacial Surgery São Paulo State University, Araraquara, Brazil, and from the Clinic of Oral and Maxillofacial Surgery at the University of Frankfurt, Germany. The 45 fractures of the mandibular angle were treated with a rectangular grid miniplate of a 2.0-mm system by an intraoral approach with monocortical screws. Clinical evaluations were postoperatively performed at 15 and 30 days and 3 and 6 months, and the complications encountered were recorded and treated. The infection rate was 4.44% (2 patients), and in 1 patient it was necessary to replace hardware. This patient also had a fracture of the left mandibular body; 3 patients (6.66%) had minor occlusal changes that have been resolved with small occlusal adjustments. Before surgery, 15 patients (33.33%) presented with hypoesthesia of the inferior alveolar nerve; 4 (8.88%) had this change until the last clinical control, at 6 months. The rectangular grid miniplate used in this study was stable for the treatment of simple mandibular angle fractures through intraoral access, with low complication rates, easy handling, and easy adjustment, with a low cost. Concomitant mandibular fracture may increase the rate of complications. This plate should be indicated in fractures with sufficient interfragmentary contact. Copyright © 2011 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  8. Effect of elliptic or circular holes on the stress distribution in plates of wood or plywood considered as orthotropic materials

    Science.gov (United States)

    C. B. Smith

    1944-01-01

    This is a mathematical analysis of the stress distribution existing near a hole in a wood or plywood plate subjected to tension, as, for example, near holes in the tension flanges of wood box beams. It is assumed that the strains are small and remain within the proportional limit. In this analysis a large, rectangular, orthotropic plate with a small elliptic hole at...

  9. Determination of Minimised Kt Values and Boundary Shapes for a Class of Quasi-Rectangular Holes in Infinite Plates

    Science.gov (United States)

    2015-07-01

    COMPUTING SHAPES AND STRESS DISTRIBUTIONS FOR QUASI-RECTANGULAR HOLES USING EXCEL VBA .......... 35 APPENDIX B: LISTING OF FADD2D INPUT DECK FOR STRESS...from which Kt values may be readily calculated, have been implemented in a Microsoft Excel spreadsheet using the Visual Basic for Applications ( VBA ...Professor Mark E Mear, University of Texas at Austin, and Professor James C Newman Jr, Mississippi State University, for providing access to the

  10. Mapping from rectangular to harmonic representation

    International Nuclear Information System (INIS)

    Schneider, W.; Bateman, G.

    1986-08-01

    An algorithm is developed to determine the Fourier harmonics representing the level contours of a scalar function given on a rectangular grid. This method is applied to the problem of computing the flux coordinates and flux surface average needed for 1-1/2-D transport codes and MHD stability codes from an equilibrium flux function given on a rectangular grid

  11. Comparative thermal buckling analysis of functionally graded plate

    Directory of Open Access Journals (Sweden)

    Čukanović Dragan V.

    2017-01-01

    Full Text Available A thermal buckling analysis of functionally graded thick rectangular plates accord¬ing to von Karman non-linear theory is presented. The material properties of the functionally graded plate, except for the Poisson’s ratio, were assumed to be graded in the thickness direction, according to a power-law distribution, in terms of the volume fractions of the metal and ceramic constituents. Formulations of equilibrium and stability equations are derived using the high order shear deformation theory based on different types of shape functions. Analytical method for determination of the critical buckling temperature for uniform increase of temperature, linear and non-linear change of temperature across thickness of a plate is developed. Numeri¬cal results were obtained in МATLAB software using combinations of symbolic and numeric values. The paper presents comparative results of critical buckling tempera¬ture for different types of shape functions. The accuracy of the formulation presented is verified by comparing to results available from the literature.

  12. Design proposal for ultimate shear strength of tapered steel plate girders

    Directory of Open Access Journals (Sweden)

    A. Bedynek

    2017-03-01

    Full Text Available Numerous experimental and numerical studies on prismatic plate girders subjected to shear can be found in the literature. However, the real structures are frequently designed as non-uniform structural elements. The main objective of the research is the development of a new proposal for the calculation of the ultimate shear resistance of tapered steel plate girders taking into account the specific behaviour of such members. A new mechanical model is presented in the paper and it is used to show the differences between the behaviour of uniform and tapered web panels subjected to shear. EN 1993-1-5 design specifications for the determination of the shear strength for rectangular plates are improved in order to assess the shear strength of tapered elements. Numerical studies carried out on tapered steel plate girders subjected to shear lead to confirm the suitability of the mechanical model and the proposed design expression.

  13. Critical heat flux correlation for thin rectangular channels

    International Nuclear Information System (INIS)

    Tanaka, Futoshi; Mishima, Kaichiro; Hibiki, Takashi

    2007-01-01

    The effect of heated length on Critical heat flux (CHF) in thin rectangular channels was studied based on CHF data obtained under atmospheric pressure. CHF in small channels has been widely studied in the past decades but most of the studies are related to CHF in round tubes. Although basic mechanisms of burnout in thin rectangular channels are similar to tubes, applicability of CHF correlations for tubes to rectangular channels are questionable since CHF in rectangular channels are affected by the existence of non-heated walls and the non-circular geometry of channel circumference. Several studies of CHF in thin rectangular channels have been reported in relation to thermal hydraulic design of research reactors and neutron source targets and CHF correlations have been proposed, but the studies mostly focus on CHFs under geometrical conditions of the application of interest. In his study, existing CHF data obtained in thin rectangular channels were collected and the effect of heated length on CHF was examined. Existing CHF correlations were verified with positive quality flow CHF data but none of the correlations successfully reproduced the CHF for a wide range of heated length. A new CHF correlation for qualify region applicable to a wide range of heated length was developed based on the collected data. (author)

  14. Numerical investigation of coalescing plate system to understand the separation of water and oil in water treatment plant of petroleum industry

    Directory of Open Access Journals (Sweden)

    Sedat Yayla

    2017-01-01

    Full Text Available The most widely utilized process of produced water treatment is considered to be use of coalescing or corrugated plate systems in the oil industry because these systems have promising results in the acceleration of the separation process. Even use of corrugated plate systems seem to be effective in separation processes, the geometrical parameters of the plate system could greatly influence the performance of separation process. In this study, a two-dimensional computational fluid dynamics model for coalescing plates was developed to investigate Reynolds number and plate hole shape on separation efficiency. Spacing between plates was set to 12 mm while fluid mixture’s Reynolds number varied between 5 and 45 for the computational model. Hole profile and dimensions were determined to be cylindrical, rectangular and ellipse shapes as 10, 15 and 20 mm based on hydraulic diameter definition, respectively. Furthermore, when hole profiles of coalescing plates were chosen to be ellipse and rectangular shapes, separation efficiency nearly stayed constant regardless of hole dimension. The study also reported that change of oil fraction from 5% to 15% caused approximately 30% increase in the separation efficiency. The investigation also revealed Reynolds number of the mixture was inversely proportional to the separation efficiency. It was also found that the highest separation efficiency was obtained for a cylindrical shape with a hole diameter of 15 mm when distance between plates was 12 mm and Reynolds number was 18.

  15. Vibration analysis of partially cracked plate submerged in fluid

    Science.gov (United States)

    Soni, Shashank; Jain, N. K.; Joshi, P. V.

    2018-01-01

    The present work proposes an analytical model for vibration analysis of partially cracked rectangular plates coupled with fluid medium. The governing equation of motion for the isotropic plate based on the classical plate theory is modified to accommodate a part through continuous line crack according to simplified line spring model. The influence of surrounding fluid medium is incorporated in the governing equation in the form of inertia effects based on velocity potential function and Bernoulli's equations. Both partially and totally submerged plate configurations are considered. The governing equation also considers the in-plane stretching due to lateral deflection in the form of in-plane forces which introduces geometric non-linearity into the system. The fundamental frequencies are evaluated by expressing the lateral deflection in terms of modal functions. The assessment of the present results is carried out for intact submerged plate as to the best of the author's knowledge the literature lacks in analytical results for submerged cracked plates. New results for fundamental frequencies are presented as affected by crack length, fluid level, fluid density and immersed depth of plate. By employing the method of multiple scales, the frequency response and peak amplitude of the cracked structure is analyzed. The non-linear frequency response curves show the phenomenon of bending hardening or softening and the effect of fluid dynamic pressure on the response of the cracked plate.

  16. Analytical determination of size-dependent natural frequencies of fully clamped rectangular microplates based on the modified couple stress theory

    Energy Technology Data Exchange (ETDEWEB)

    Askari, Amir R.; Tahani, Masoud [Ferdowsi University of Mashhad, Mashhad (Iran, Islamic Republic of)

    2015-05-15

    This paper presents an analytical and size-dependent model for vibrational analysis of fully clamped rectangular microplates. Modified couple stress theory (MCST) and the Kirchhoff plate model are considered, and Hamilton's principle is employed to derive the size dependent equation of motion that accounts for the effect of residual stresses. The natural frequencies of the microplate are extracted analytically by extended Kantorovich method. The present findings are validated with the available results in the literature, and an excellent agreement is observed between them. In addition, a parametric study is conducted to demonstrate the significant effects of couple stress components on the natural frequencies of fully clamped microplates. The ratio of MCST natural frequencies to those obtained with classical theory depends only on the Poisson's ratio of the plate and is independent of the aspect ratio of the plate for cases with no residual stresses.

  17. Analytical determination of size-dependent natural frequencies of fully clamped rectangular microplates based on the modified couple stress theory

    International Nuclear Information System (INIS)

    Askari, Amir R.; Tahani, Masoud

    2015-01-01

    This paper presents an analytical and size-dependent model for vibrational analysis of fully clamped rectangular microplates. Modified couple stress theory (MCST) and the Kirchhoff plate model are considered, and Hamilton's principle is employed to derive the size dependent equation of motion that accounts for the effect of residual stresses. The natural frequencies of the microplate are extracted analytically by extended Kantorovich method. The present findings are validated with the available results in the literature, and an excellent agreement is observed between them. In addition, a parametric study is conducted to demonstrate the significant effects of couple stress components on the natural frequencies of fully clamped microplates. The ratio of MCST natural frequencies to those obtained with classical theory depends only on the Poisson's ratio of the plate and is independent of the aspect ratio of the plate for cases with no residual stresses.

  18. Cooling of rectangular bars

    International Nuclear Information System (INIS)

    Frainer, V.J.

    1979-01-01

    A solution of the time-transient Heat Transfer Differential Equation in rectangular coordinates is presented, leading to a model which describes the temperature drop with time in rectangular bars. It is similar to an other model for cilindrical bars which has been previously developed in the Laboratory of Mechanical Metallurgy of UFRGS. Following these models, a generalization has been made, which permits cooling time evaluation for all profiles. These results are compared with experimental laboratory data in the 1200 to 800 0 C range. Some other existing models were also studied which have the purpose of studing the same phenomenon. Their mathematical forms and their evaluated values are analyzed and compared with experimental ones. (Author) [pt

  19. g-Weak Contraction in Ordered Cone Rectangular Metric Spaces

    Directory of Open Access Journals (Sweden)

    S. K. Malhotra

    2013-01-01

    Full Text Available We prove some common fixed-point theorems for the ordered g-weak contractions in cone rectangular metric spaces without assuming the normality of cone. Our results generalize some recent results from cone metric and cone rectangular metric spaces into ordered cone rectangular metric spaces. Examples are provided which illustrate the results.

  20. Microscopic Holography for flow over rough plate

    Science.gov (United States)

    Talapatra, Siddharth; Hong, Jiarong; Lu, Yuan; Katz, Joseph

    2008-11-01

    Our objective is to measure the near wall flow structures in a turbulent channel flow over a rough wall. In-line microscopic holographic PIV can resolve the 3-D flow field in a small sample volume, but recording holograms through a rough surface is a challenge. To solve this problem, we match the refractive indices of the fluid with that of the wall. Proof of concept tests involve an acrylic plate containing uniformly distributed, closely packed 0.45mm high pyramids with slope angle of 22^^o located within a concentrated sodium iodide solution. Holograms recorded by a 4864 x 3248 pixel digital camera at 10X magnification provide a field of view of 3.47mm x 2.32mm and pixel resolution of 0.714 μm. Due to index matching, reconstructed seed particles can be clearly seen over the entire volume, with only faint traces with the rough wall that can be removed. Planned experiments will be performed in a 20 x 5 cm rectangular channel with the top and bottom plates having the same roughness as the sample plate.

  1. A Mechanistic Model of Onset of Flow Instability Due to Mergence of Bubble Layers in a Vertical Narrow Rectangular Channel

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Juh Yung; Chang, Soon Heung; Jeong, Yong [KAIST, Daejeon (Korea, Republic of)

    2016-05-15

    The onset of flow instability (OFI) is the one of important boiling phenomena since it may induce the premature critical heat flux (CHF) at the lowest heat flux level due to sudden flow excursion in a single channel of multichannel configuration. Especially prediction of OFI for narrow rectangular channel is very crucial in relevant to thermal-hydraulic design and safety analysis of open pool-type research reactors (RRs) using plate-type fuels. Based on high speed video (HSV) technique, the authors observed and determined that OFI and the minimum premature CHF in a narrow rectangular channel are induced by abrupt pressure drop fluctuation due to the mergence of facing bubble boundary layers (BLs) on opposite boiling surfaces. In this study, new mechanistic OFI model for narrow rectangular channel heated on both sides has been derived, which satisfies with the real triggering phenomena. Force balance approach was used for modeling of the maximum BLT since the quantity is comparable to the bubble departure diameter. From the validation with OFI database, it was shown that the new model fairly well predicts OFI heat flux for wide range of conditions.

  2. Predictions and measurements of residual stress in repair welds in plates

    Energy Technology Data Exchange (ETDEWEB)

    Brown, T.B. [Mitsui Babcock Energy Limited, Technology and Engineering, Porterfield Road, Renfrew, PA4 8DJ, Scotland (United Kingdom)]. E-mail: bbrown@mitsuibabcock.com; Dauda, T.A. [Mitsui Babcock Energy Limited, Technology and Engineering, Porterfield Road, Renfrew, PA4 8DJ, Scotland (United Kingdom); Truman, C.E. [Department of Mechanical Engineering, University of Bristol, Bristol BS8 1TR, England (United Kingdom); Smith, D.J. [Department of Mechanical Engineering, University of Bristol, Bristol BS8 1TR (United Kingdom); Memhard, D. [Fraunhofer-Institut fuer Werkstoffmechanik, Freiburg (Germany); Pfeiffer, W. [Fraunhofer-Institut fuer Werkstoffmechanik, Freiburg (Germany)

    2006-11-15

    This paper presents the work, from the European Union FP-5 project ELIXIR, on a series of rectangular repair welds in P275 and S690 steels to validate the numerical modelling techniques used in the determination of the residual stresses generated during the repair process. The plates were 1,000 mm by 800 mm with thicknesses of 50 and 100 mm. The repair welds were 50%, 75% and 100% through the plate thickness. The repair welds were modelled using the finite element method to make predictions of the as-welded residual stress distributions. These predictions were compared with surface-strain measurements made on the parent plates during welding and found to be in good agreement. Through-thickness residual stress measurements were obtained from the test plates through, and local to, the weld repairs using the deep hole drilling technique. Comparisons between the measurements and the finite element predictions generally showed good agreement, thus providing confidence in the method.

  3. Predictions and measurements of residual stress in repair welds in plates

    International Nuclear Information System (INIS)

    Brown, T.B.; Dauda, T.A.; Truman, C.E.; Smith, D.J.; Memhard, D.; Pfeiffer, W.

    2006-01-01

    This paper presents the work, from the European Union FP-5 project ELIXIR, on a series of rectangular repair welds in P275 and S690 steels to validate the numerical modelling techniques used in the determination of the residual stresses generated during the repair process. The plates were 1,000 mm by 800 mm with thicknesses of 50 and 100 mm. The repair welds were 50%, 75% and 100% through the plate thickness. The repair welds were modelled using the finite element method to make predictions of the as-welded residual stress distributions. These predictions were compared with surface-strain measurements made on the parent plates during welding and found to be in good agreement. Through-thickness residual stress measurements were obtained from the test plates through, and local to, the weld repairs using the deep hole drilling technique. Comparisons between the measurements and the finite element predictions generally showed good agreement, thus providing confidence in the method

  4. Experimental Study of Flexible Plate Vibration Control by Using Two-Loop Sliding Mode Control Strategy

    Science.gov (United States)

    Yang, Jingyu; Lin, Jiahui; Liu, Yuejun; Yang, Kang; Zhou, Lanwei; Chen, Guoping

    2017-08-01

    It is well known that intelligent control theory has been used in many research fields, novel modeling method (DROMM) is used for flexible rectangular active vibration control, and then the validity of new model is confirmed by comparing finite element model with new model. In this paper, taking advantage of the dynamics of flexible rectangular plate, a two-loop sliding mode (TSM) MIMO approach is introduced for designing multiple-input multiple-output continuous vibration control system, which can overcome uncertainties, disturbances or unstable dynamics. An illustrative example is given in order to show the feasibility of the method. Numerical simulations and experiment confirm the effectiveness of the proposed TSM MIMO controller.

  5. Equilibrium approach in the derivation of differential equations for ...

    African Journals Online (AJOL)

    In this paper, the differential equations of Mindlin plates are derived from basic principles by simultaneous satisfaction of the differential equations of equilibrium, the stress-strain laws and the strain-displacement relations for isotropic, homogenous linear elastic materials. Equilibrium method was adopted in the derivation.

  6. Nigerian Journal of Technology - Vol 36, No 2 (2017)

    African Journals Online (AJOL)

    ... in the derivation of differential equations for homogeneous isotropic mindlin plates ... Optimised intake stroke analysis for flat and dome head pistons · EMAIL FREE ... circular reservoirs under the constant pressure outer boundary condition ... Comparative analysis of diagnostic applications of autoscan tools on vehicle ...

  7. A New Hyperbolic Shear Deformation Theory for Bending Analysis of Functionally Graded Plates

    Directory of Open Access Journals (Sweden)

    Tahar Hassaine Daouadji

    2012-01-01

    Full Text Available Theoretical formulation, Navier’s solutions of rectangular plates based on a new higher order shear deformation model are presented for the static response of functionally graded plates. This theory enforces traction-free boundary conditions at plate surfaces. Shear correction factors are not required because a correct representation of transverse shearing strain is given. Unlike any other theory, the number of unknown functions involved is only four, as against five in case of other shear deformation theories. The mechanical properties of the plate are assumed to vary continuously in the thickness direction by a simple power-law distribution in terms of the volume fractions of the constituents. Numerical illustrations concern flexural behavior of FG plates with metal-ceramic composition. Parametric studies are performed for varying ceramic volume fraction, volume fractions profiles, aspect ratios, and length to thickness ratios. Results are verified with available results in the literature. It can be concluded that the proposed theory is accurate and simple in solving the static bending behavior of functionally graded plates.

  8. Rapid State Space Modeling Tool for Rectangular Wing Aeroservoelastic Studies

    Science.gov (United States)

    Suh, Peter M.; Conyers, Howard Jason; Mavris, Dimitri N.

    2015-01-01

    This report introduces a modeling and simulation tool for aeroservoelastic analysis of rectangular wings with trailing-edge control surfaces. The inputs to the code are planform design parameters such as wing span, aspect ratio, and number of control surfaces. Using this information, the generalized forces are computed using the doublet-lattice method. Using Roger's approximation, a rational function approximation is computed. The output, computed in a few seconds, is a state space aeroservoelastic model which can be used for analysis and control design. The tool is fully parameterized with default information so there is little required interaction with the model developer. All parameters can be easily modified if desired. The focus of this report is on tool presentation, verification, and validation. These processes are carried out in stages throughout the report. The rational function approximation is verified against computed generalized forces for a plate model. A model composed of finite element plates is compared to a modal analysis from commercial software and an independently conducted experimental ground vibration test analysis. Aeroservoelastic analysis is the ultimate goal of this tool, therefore, the flutter speed and frequency for a clamped plate are computed using damping-versus-velocity and frequency-versus-velocity analysis. The computational results are compared to a previously published computational analysis and wind-tunnel results for the same structure. A case study of a generic wing model with a single control surface is presented. Verification of the state space model is presented in comparison to damping-versus-velocity and frequency-versus-velocity analysis, including the analysis of the model in response to a 1-cos gust.

  9. Thermal resistance of a convectively cooled plate with applied heat flux and variable internal heat generation

    International Nuclear Information System (INIS)

    Venkataraman, N.S.; Cardoso, H.P.; Oliveira Filho, O.B. de

    1981-01-01

    The conductive heat transfer in a rectangular plate with nonuniform internal heat generation, with one end convectively cooled and a part of the opposite end subjected to external heat flux is considered. The remaining part of this end as well as the other two sides are thermally insulated. The governing differential equation is solved by a finite difference scheme. The variation of the thermal resistance with Biot modulus, the plate geometry, the internal heat generation parameter and the type of profile of internal heat generation is discussed. (author) [pt

  10. Equilibrium paths of an imperfect plate with respect to its aspect ratio

    Science.gov (United States)

    Psotny, Martin

    2017-07-01

    The stability analysis of a rectangular plate loaded in compression is presented, a specialized code based on FEM has been created. Special finite element with 48 degrees of freedom has been used for analysis. The nonlinear finite element method equations are derived from the variational principle of minimum of total potential energy. To trace the complete nonlinear equilibrium paths, the Newton-Raphson iteration algorithm is used, load versus displacement control was changed during the calculation process. The peculiarities of the effects of the initial imperfections on the load-deflection paths are investigated with respect to aspect ratio of the plate. Special attention is paid to the influence of imperfections on the post-critical buckling mode.

  11. Quantification of the spatial strain distribution of scoliosis using a thin-plate spline method.

    Science.gov (United States)

    Kiriyama, Yoshimori; Watanabe, Kota; Matsumoto, Morio; Toyama, Yoshiaki; Nagura, Takeo

    2014-01-03

    The objective of this study was to quantify the three-dimensional spatial strain distribution of a scoliotic spine by nonhomogeneous transformation without using a statistically averaged reference spine. The shape of the scoliotic spine was determined from computed tomography images from a female patient with adolescent idiopathic scoliosis. The shape of the scoliotic spine was enclosed in a rectangular grid, and symmetrized using a thin-plate spline method according to the node positions of the grid. The node positions of the grid were determined by numerical optimization to satisfy symmetry. The obtained symmetric spinal shape was enclosed within a new rectangular grid and distorted back to the original scoliotic shape using a thin-plate spline method. The distorted grid was compared to the rectangular grid that surrounded the symmetrical spine. Cobb's angle was reduced from 35° in the scoliotic spine to 7° in the symmetrized spine, and the scoliotic shape was almost fully symmetrized. The scoliotic spine showed a complex Green-Lagrange strain distribution in three dimensions. The vertical and transverse compressive/tensile strains in the frontal plane were consistent with the major scoliotic deformation. The compressive, tensile and shear strains on the convex side of the apical vertebra were opposite to those on the concave side. These results indicate that the proposed method can be used to quantify the three-dimensional spatial strain distribution of a scoliotic spine, and may be useful in quantifying the deformity of scoliosis. © 2013 Elsevier Ltd. All rights reserved.

  12. Random Young diagrams in a Rectangular Box

    DEFF Research Database (Denmark)

    Beltoft, Dan; Boutillier, Cédric; Enriquez, Nathanaël

    We exhibit the limit shape of random Young diagrams having a distribution proportional to the exponential of their area, and confined in a rectangular box. The Ornstein-Uhlenbeck bridge arises from the fluctuations around the limit shape.......We exhibit the limit shape of random Young diagrams having a distribution proportional to the exponential of their area, and confined in a rectangular box. The Ornstein-Uhlenbeck bridge arises from the fluctuations around the limit shape....

  13. Rectangular-cladding silicon slot waveguide with improved nonlinear performance

    Science.gov (United States)

    Huang, Zengzhi; Huang, Qingzhong; Wang, Yi; Xia, Jinsong

    2018-04-01

    Silicon slot waveguides have great potential in hybrid silicon integration to realize nonlinear optical applications. We propose a rectangular-cladding hybrid silicon slot waveguide. Simulation result shows that, with a rectangular-cladding, the slot waveguide can be formed by narrower silicon strips, so the two-photon absorption (TPA) loss in silicon is decreased. When the cladding material is a nonlinear polymer, the calculated TPA figure of merit (FOMTPA) is 4.4, close to the value of bulk nonlinear polymer of 5.0. This value confirms the good nonlinear performance of rectangular-cladding silicon slot waveguides.

  14. Oblique Wave-Induced Responses of A VLFS Edged with A Pair of Inclined Perforated Plates

    Science.gov (United States)

    Cheng, Yong; Ji, Chun-yan; Zhai, Gang-jun; Oleg, Gaidai

    2018-03-01

    This paper is concerned with the hydroelastic responses of a mat-like, rectangular very large floating structure (VLFS) edged with a pair of horizontal/inclined perforated anti-motion plates in the context of the direct coupling method. The updated Lagrangian formulae are applied to establish the equilibrium equations of the VLFS and the total potential formula is employed for fluids in the numerical model including the viscous effect of the perforated plates through the Darcy's law. The hybrid finite element-boundary element (FE-BE) method is implemented to determine the response reduction of VLFS with attached perforated plates under various oblique incident waves. Also, the numerical solutions are validated against a series of experimental tests. The effectiveness of the attached perforated plates in reducing the deflections of the VLFS can be significantly improved by selecting the proper design parameters such as the porous parameter, submergence depth, plate width and inclination angle for the given sea conditions.

  15. Wakefield excitation by a sequence of relativistic electron bunches in dielectric waveguides of rectangular cross-section of various configurations

    International Nuclear Information System (INIS)

    Kiselev, V.A.; Linnik, A.F.; Mirnyj, V.I.; Onishchenko, I.N.; Sotnikov, G.V.; Uskov, V.V.

    2008-01-01

    The possibility to enhance the efficiency of wake wave excitation in dielectric waveguides of rectangular cross-section was investigated by increase of electron bunches coupling with excited wakefield that was achieved by decrease of transit channel cross-section. At that for each configuration the required changes of dielectric plates size were made to for maintain the coincidence concurrence of bunch repetition frequency and frequency of the principal transverse mode of the corresponding dielectric waveguide. It is established, the decrease of transit channel leading to essential changing of topography of total field excited wake wave

  16. Towards characterizing graphs with a sliceable rectangular dual

    NARCIS (Netherlands)

    Kusters, V.; Speckmann, B.; Di Giacomo, E.; Lubiw, A.

    2015-01-01

    Let G be a plane triangulated graph. A rectangular dual of G is a partition of a rectangle R into a set R of interior-disjoint rectangles, one for each vertex, such that two regions are adjacent if and only if the corresponding vertices are connected by an edge. A rectangular dual is sliceable if it

  17. Stiffness of sphere–plate contacts at MHz frequencies: dependence on normal load, oscillation amplitude, and ambient medium

    Directory of Open Access Journals (Sweden)

    Jana Vlachová

    2015-03-01

    Full Text Available The stiffness of micron-sized sphere–plate contacts was studied by employing high frequency, tangential excitation of variable amplitude (0–20 nm. The contacts were established between glass spheres and the surface of a quartz crystal microbalance (QCM, where the resonator surface had been coated with either sputtered SiO2 or a spin-cast layer of poly(methyl methacrylate (PMMA. The results from experiments undertaken in the dry state and in water are compared. Building on the shifts in the resonance frequency and resonance bandwidth, the instrument determines the real and the imaginary part of the contact stiffness, where the imaginary part quantifies dissipative processes. The method is closely analogous to related procedures in AFM-based metrology. The real part of the contact stiffness as a function of normal load can be fitted with the Johnson–Kendall–Roberts (JKR model. The contact stiffness was found to increase in the presence of liquid water. This finding is tentatively explained by the rocking motion of the spheres, which couples to a squeeze flow of the water close to the contact. The loss tangent of the contact stiffness is on the order of 0.1, where the energy losses are associated with interfacial processes. At high amplitudes partial slip was found to occur. The apparent contact stiffness at large amplitude depends linearly on the amplitude, as predicted by the Cattaneo–Mindlin model. This finding is remarkable insofar, as the Cattaneo–Mindlin model assumes Coulomb friction inside the sliding region. Coulomb friction is typically viewed as a macroscopic concept, related to surface roughness. An alternative model (formulated by Savkoor, which assumes a constant frictional stress in the sliding zone independent of the normal pressure, is inconsistent with the experimental data. The apparent friction coefficients slightly increase with normal force, which can be explained by nanoroughness. In other words, contact splitting

  18. Acoustic impact on the laminated plates placed between barriers

    Science.gov (United States)

    Paimushin, V. N.; Gazizullin, R. K.; Fedotenkov, G. V.

    2016-11-01

    On the basis of previously derived equations, analytical solutions are established on the forced vibrations of two-layer and three-layers rectangular plates hinged in an opening of absolutely rigid walls during the transmission of monoharmonic sound waves. It is assumed that the partition wall is situated between two absolutely rigid barriers, one of them by harmonic oscillation with a given displacements amplitude on the plate forms the incident sound wave, and the other is stationary and has a coating of deformable energy absorbing material with high damping properties. The behavior of acoustic environments in the spaces between the deformable plate and the barriers described by classical wave equation based on the ideal compressible fluid model. To describe the process of dynamic deformation of the energy absorbing coating of fixed barrier, two-dimensional equations of motion based on the use of models transversely soft layer are derived with a linear approximation of the displacement field in the thickness direction of the coating and taking into account the damping properties of the material and the hysteresis model for it. The influence of the physical and mechanical properties of the concerned mechanical system and the frequency of the incident sound wave on the parameters of its insulation properties of the plate, as well as on the parameters of the stress-strain state of the plate has been analyzed.

  19. Fractional-order positive position feedback compensator for active vibration control of a smart composite plate

    Science.gov (United States)

    Marinangeli, L.; Alijani, F.; HosseinNia, S. Hassan

    2018-01-01

    In this paper, Active Vibration Control (AVC) of a rectangular carbon fibre composite plate with free edges is presented. The plate is subjected to out-of-plane excitation by a modal vibration exciter and controlled by Macro Fibre Composite (MFC) transducers. Vibration measurements are performed by using a Laser Doppler Vibrometer (LDV) system. A fractional-order Positive Position Feedback (PPF) compensator is proposed, implemented and compared to the standard integer-order PPF. MFC actuator and sensor are positioned on the plate based on maximal modal strain criterion, so as to control the second natural mode of the plate. Both integer and fractional-order PPF allowed for the effective control of the second mode of vibration. However, the newly proposed fractional-order controller is found to be more efficient in achieving the same performance with less actuation voltage. Moreover, it shows promising performance in reducing spillover effect due to uncontrolled modes.

  20. Flow induced deformation and collapse of a thin rectangular plate with application to the Engineering Test Reactor nuclear fuel elements

    International Nuclear Information System (INIS)

    Davis, C.D.

    1981-01-01

    This work examines a single flat fuel plate bounded by two channels and determines static plate deflections, resultant forces and bending stresses due to pressure differential and hydrodynamic loadings. The classical then reactangular plate equations are used to model the fuel plate. These equations contain as an input the hydrodynamic loading function for modeling the fluid-structural interaction. Two models of the channel flow are developed. One assumes the accelerating potential core flow is laminar with developing two-dimensional laminar boundary layers being formed on the channel walls. The Schlichting entry length solution for developing laminar flow is found to be valid the entire length of the channel. The second model assumes the core flow is fully-developed turbulent the entire length of the channel. Hydrodynamic loading functions are developed for both flow models containing parameters for fluid density, fluid velocity, Reynolds number and channel and plate dimensions. Hence the effects of each parameter can be examined independently. A criterion is developed for predicting ETR fuel plate collapse at high channel flow velocities, 1067 cm/s (420 in/sec) (R/sub e/ = 60,000). The criterion predicts that in order to prevent ETR plate collapse the inlet velocities between channels must not differ by more than 2%

  1. Three-dimensional inverse transient heat transfer analysis of thick functionally graded plates

    Energy Technology Data Exchange (ETDEWEB)

    Haghighi, M.R. Golbahar; Malekzadeh, P. [Department of Mechanical Engineering, School of Engineering, Persian Gulf University, Bushehr 75168 (Iran); Eghtesad, M. [Department of Mechanical Engineering, School of Engineering, Shiraz University, Shiraz 71348-51154 (Iran); Necsulescu, D.S. [Department of Mechanical Engineering, Faculty of Engineering, University of Ottawa, Ottawa, Ontario (Canada)

    2009-03-15

    In this paper, a three-dimensional transient inverse heat conduction (IHC) procedure is presented to estimate the unknown boundary heat flux of thick functionally graded (FG) plates. For this purpose, the conjugate gradient method (CGM) in conjunction with adjoint problem is used. A recently developed three-dimensional efficient hybrid method is employed to solve variable-coefficient initial-boundary-value differential equations of direct problem as a part of the inverse solution. The accuracy of the inverse analysis is examined by simulating the exact and noisy data for problems with different types of boundary conditions and material properties. In addition to rectangular domain, skew plates are considered. The results obtained show good accuracy for the estimation of boundary heat fluxes. (author)

  2. Analysis of High Tc Superconducting Rectangular Microstrip Patches over Ground Planes with Rectangular Apertures in Substrates Containing Anisotropic Materials

    Directory of Open Access Journals (Sweden)

    Abderraouf Messai

    2013-01-01

    Full Text Available A rigorous full-wave analysis of high Tc superconducting rectangular microstrip patch over ground plane with rectangular aperture in the case where the patch is printed on a uniaxially anisotropic substrate material is presented. The dyadic Green’s functions of the considered structure are efficiently determined in the vector Fourier transform domain. The effect of the superconductivity of the patch is taken into account using the concept of the complex resistive boundary condition. The accuracy of the analysis is tested by comparing the computed results with measurements and previously published data for several anisotropic substrate materials. Numerical results showing variation of the resonant frequency and the quality factor of the superconducting antenna with regard to operating temperature are given. Finally, the effects of uniaxial anisotropy in the substrate on the resonant frequencies of different TM modes of the superconducting microstrip antenna with rectangular aperture in the ground plane are presented.

  3. Study on the output factors of asymmetrical rectangular electron beam field

    International Nuclear Information System (INIS)

    Chen Yinghai; Yang Yueqin; Ma Yuhong; Zheng Jin; Zou Lijuan

    2009-01-01

    Objective: To evaluate the variant regularity of the output factors of asymmetrical rectangular electron beam field. Methods: The output factors of three special fields with different applicators and energies were measured by ionization chamber method at different off-axis distances. Then deviations of the output factors between asymmetrical and symmetric rectangular fields were calculated. Results: The changes of output factor with different off-axis distances in asymmetrical rectangular fields were basically consistent with those in standard square fields with the same applicator. It revealed that the output factor of asymmetrical rectangular field was related with the off-axis ratio of standard square field. Applicator and field size did not show obvious influence on the output factor. Conclusions: The output factor changes of asymmetrical rectangular field are mainly correlated with the off-axis ratio of standard square field. The correction of the output factor is determined by the off-axis ratio changes in standard square field. (authors)

  4. Ground cross-modal impedance as a tool for analyzing ground/plate interaction and ground wave propagation.

    Science.gov (United States)

    Grau, L; Laulagnet, B

    2015-05-01

    An analytical approach is investigated to model ground-plate interaction based on modal decomposition and the two-dimensional Fourier transform. A finite rectangular plate subjected to flexural vibration is coupled with the ground and modeled with the Kirchhoff hypothesis. A Navier equation represents the stratified ground, assumed infinite in the x- and y-directions and free at the top surface. To obtain an analytical solution, modal decomposition is applied to the structure and a Fourier Transform is applied to the ground. The result is a new tool for analyzing ground-plate interaction to resolve this problem: ground cross-modal impedance. It allows quantifying the added-stiffness, added-mass, and added-damping from the ground to the structure. Similarity with the parallel acoustic problem is highlighted. A comparison between the theory and the experiment shows good matching. Finally, specific cases are investigated, notably the influence of layer depth on plate vibration.

  5. Heat Transfer Characteristics during Boiling of Immiscible Liquids Flowing in Narrow Rectangular Heated Channels

    Directory of Open Access Journals (Sweden)

    Yasuhisa Shinmoto

    2017-11-01

    Full Text Available The use of immiscible liquids for cooling of surfaces with high heat generation density is proposed based on the experimental verification of its superior cooling characteristics in fundamental systems of pool boiling and flow boiling in a tube. For the purpose of practical applications, however, heat transfer characteristics due to flow boiling in narrow rectangular channels with different small gap sizes need to be investigated. The immiscible liquids employed here are FC72 and water, and the gap size is varied as 2, 1, and 0.5 mm between parallel rectangular plates of 30 mm × 175 mm, where one plate is heated. To evaluate the effect of gap size, the heat transfer characteristics are compared at the same inlet velocity. The generation of large flattened bubbles in a narrow gap results in two opposite trends of the heat transfer enhancement due to thin liquid film evaporation and of the deterioration due to the extension of dry patch in the liquid film. The situation is the same as that observed for pure liquids. The latter negative effect is emphasized for extremely small gap sizes if the flow rate ratio of more-volatile liquid to the total is not reduced. The addition of small flow rate of less-volatile liquid can increase the critical heat flux (CHF of pure more-volatile liquid, while the surface temperature increases at the same time and assume the values between those for more-volatile and less-volatile liquids. By the selection of small flow rate ratio of more-volatile liquid, the surface temperature of pure less-volatile liquid can be decreased without reducing high CHF inherent in the less-volatile liquid employed. The trend of heat transfer characteristics for flow boiling of immiscible mixtures in narrow channels is more sensitive to the composition compared to the flow boiling in a round tube.

  6. A Characterization of Rectangular Distributions

    OpenAIRE

    Terrell, George R.

    1983-01-01

    It is well known that the smaller and the larger of a random sample of size two are positively correlated. The coefficient of correlation is at most one-half, and the upper bound is attained only for rectangular distributions.

  7. Buckling analysis of rectangular composite plates with rectangular ...

    Indian Academy of Sciences (India)

    In aeronautical, marine and automobile industries the use of composite laminates .... load of fibre-reinforced plastic square panels using finite element method. .... lar cutout i.e d/b = 0.1 and β =0, the reduction in buckling load by increasing c/b ...

  8. Method and structure for cache aware transposition via rectangular subsections

    Science.gov (United States)

    Gustavson, Fred Gehrung; Gunnels, John A

    2014-02-04

    A method and structure for transposing a rectangular matrix A in a computer includes subdividing the rectangular matrix A into one or more square submatrices and executing an in-place transposition for each of the square submatrices A.sub.ij.

  9. Errors generated with the use of rectangular collimation

    International Nuclear Information System (INIS)

    Parks, E.T.

    1991-01-01

    This study was designed to determine whether various techniques for achieving rectangular collimation generate different numbers and types of errors and remakes and to determine whether operator skill level influences errors and remakes. Eighteen students exposed full-mouth series of radiographs on manikins with the use of six techniques. The students were grouped according to skill level. The radiographs were evaluated for errors and remakes resulting from errors in the following categories: cone cutting, vertical angulation, and film placement. Significant differences were found among the techniques in cone cutting errors and remakes, vertical angulation errors and remakes, and total errors and remakes. Operator skill did not appear to influence the number or types of errors or remakes generated. Rectangular collimation techniques produced more errors than did the round collimation techniques. However, only one rectangular collimation technique generated significantly more remakes than the other techniques

  10. A two-component NZRI metamaterial based rectangular cloak

    Directory of Open Access Journals (Sweden)

    Sikder Sunbeam Islam

    2015-10-01

    Full Text Available A new two-component, near zero refractive index (NZRI metamaterial is presented for electromagnetic rectangular cloaking operation in the microwave range. In the basic design a pi-shaped, metamaterial was developed and its characteristics were investigated for the two major axes (x and z-axis wave propagation through the material. For the z-axis wave propagation, it shows more than 2 GHz bandwidth and for the x-axis wave propagation; it exhibits more than 1 GHz bandwidth of NZRI property. The metamaterial was then utilized in designing a rectangular cloak where a metal cylinder was cloaked perfectly in the C-band area of microwave regime. The experimental result was provided for the metamaterial and the cloak and these results were compared with the simulated results. This is a novel and promising design for its two-component NZRI characteristics and rectangular cloaking operation in the electromagnetic paradigm.

  11. Wettability measurements of irregular shapes with Wilhelmy plate method

    Science.gov (United States)

    Park, Jaehyung; Pasaogullari, Ugur; Bonville, Leonard

    2018-01-01

    One of the most accurate methods for measuring the dynamic contact angle of liquids on solid surfaces is the Wilhelmy plate method. This method generally requires the use of rectangular samples having a constant perimeter in the liquid during advancing and receding cycles. A new formulation based on the Wilhelmy force balance equation to determine the contact angle for plate samples with irregular shapes has been developed. This method employs a profile plot obtained from an optical image to determine the perimeter (i.e. wetted length) of the sample as a function of the immersion depth. The raw force data measured by the force tensiometer is manipulated using the profile plot and the Wilhelmy equation to determine the wetting force and consequently advancing and the receding contact angle. This method is verified with both triangular and irregular PTFE samples in water, and measured contact angles are in good agreement with results from conventional regular shaped samples with a constant perimeter.

  12. Rectangular optical filter based on high-order silicon microring resonators

    Science.gov (United States)

    Bao, Jia-qi; Yu, Kan; Wang, Li-jun; Yin, Juan-juan

    2017-07-01

    The rectangular optical filter is one of the most important optical switching components in the dense wavelength division multiplexing (DWDM) fiber-optic communication system and the intelligent optical network. The integrated highorder silicon microring resonator (MRR) is one of the best candidates to achieve rectangular filtering spectrum response. In general, the spectrum response rectangular degree of the single MRR is very low, so it cannot be used in the DWDM system. Using the high-order MRRs, the bandwidth of flat-top pass band, the out-of-band rejection degree and the roll-off coefficient of the edge will be improved obviously. In this paper, a rectangular optical filter based on highorder MRRs with uniform couplers is presented and demonstrated. Using 15 coupled race-track MRRs with 10 μm in radius, the 3 dB flat-top pass band of 2 nm, the out-of-band rejection ratio of 30 dB and the rising and falling edges of 48 dB/nm can be realized successfully.

  13. Rectangular optical filter based on high-order silicon microring resonators

    Institute of Scientific and Technical Information of China (English)

    BAO Jia-qi; YU Kan; WANG Li-jun; YIN Juan-juan

    2017-01-01

    The rectangular optical filter is one of the most important optical switching components in the dense wavelength division multiplexing (DWDM) fiber-optic communication system and the intelligent optical network.The integrated highorder silicon microring resonator (MRR) is one of the best candidates to achieve rectangular filtering spectrum response.In general,the spectrum response rectangular degree of the single MRR is very low,so it cannot be used in the DWDM system.Using the high-order MRRs,the bandwidth of flat-top pass band,the out-of-band rejection degree and the roll-off coefficient of the edge will be improved obviously.In this paper,a rectangular optical filter based on highorder MRRs with uniform couplers is presented and demonstrated.Using 15 coupled race-track MRRs with 10 μm in radius,the 3 dB flat-top pass band of 2 nm,the out-of-band rejection ratio of 30 dB and the rising and falling edges of 48 dB/nm can be realized successfully.

  14. Comparison of rectangular and dual-planar positron emission mammography scanners

    International Nuclear Information System (INIS)

    Qi, Jinyi; Kuo, Chaincy; Huesman, Ronald H.; Klein, Gregory J.; Moses, William W.; Reutter, Bryan W.

    2002-01-01

    Breast imaging using dedicated positron emission tomography (PEM) has gained much interest in the medical imaging field. In this paper, we compare the performance between a rectangular geometry and a parallel dual-planar geometry. Both geometries are studied with depth of interaction (DOI) detectors and non- DOI detectors. We compare the Fisher-information matrix, lesion detection, and quantitation of the four systems. The lesion detectability is measured by the signal-to-noise ratio (SNR) of a prewhitening numerical observer for detecting a known hot spot on a uniform background. Results show that the rectangular system with DOI has the highest SNR for the detection task and the lowest bias at any given noise level for the quantitation task. They also show that for small simulated lesions the parallel dual-planar system with DOI detectors outperforms the rectangular system with non-DOI detectors, while the rectangular system with non-DOI detectors can outperform the parallel dual-planar system with DOI detectors for large simulated lesions

  15. A CPW-Fed Rectangular Ring Monopole Antenna for WLAN Applications

    Directory of Open Access Journals (Sweden)

    Sangjin Jo

    2014-01-01

    Full Text Available We present a simple coplanar waveguide- (CPW- fed rectangular ring monopole antenna designed for dual-band wireless local area network (WLAN applications. The antenna is based on a simple structure composed of a CPW feed line and a rectangular ring. Dual-band WLAN operation can be achieved by controlling the distance between the rectangular ring and the ground plane of the CPW feed line, as well as the horizontal vertical lengths of the rectangular ring. Simulated and measured data show that the antenna has a compact size of 21.4×59.4 mm2, an impedance bandwidths of 2.21–2.70 GHz and 5.04–6.03 GHz, and a reflection coefficient of less than −10 dB. The antenna also exhibits an almost omnidirectional radiation pattern. This simple compact antenna with favorable frequency characteristics therefore is attractive for applications in dual-band WLAN.

  16. Comparison of the application of plate and beam theories to the elastic dilation and interaction of PFR sub-assembly wrappers

    International Nuclear Information System (INIS)

    Moss, R.L.

    1977-10-01

    A wrapper face is assumed to be a long, narrow, rectangular plate. The mechanical interaction between adjacent dilating wrappers in contact along an axial line is discussed in terms of the theory of the bending of plates. A variational method is used to obtain neat and concise equations that determine both the interaction load and the length of the line of contact. The prime objective of the work is to compare the results obtained from plate theory with corresponding expressions from much simpler calculations based on beam theory. Numerical results indicate that the elastic dilation of a wrapper and its interaction with a neighbouring wrapper can be calculated to adequate accuracy by simple beam theory. (author)

  17. Finite element fatigue analysis of rectangular clutch spring of automatic slack adjuster

    Science.gov (United States)

    Xu, Chen-jie; Luo, Zai; Hu, Xiao-feng; Jiang, Wen-song

    2015-02-01

    The failure of rectangular clutch spring of automatic slack adjuster directly affects the work of automatic slack adjuster. We establish the structural mechanics model of automatic slack adjuster rectangular clutch spring based on its working principle and mechanical structure. In addition, we upload such structural mechanics model to ANSYS Workbench FEA system to predict the fatigue life of rectangular clutch spring. FEA results show that the fatigue life of rectangular clutch spring is 2.0403×105 cycle under the effect of braking loads. In the meantime, fatigue tests of 20 automatic slack adjusters are carried out on the fatigue test bench to verify the conclusion of the structural mechanics model. The experimental results show that the mean fatigue life of rectangular clutch spring is 1.9101×105, which meets the results based on the finite element analysis using ANSYS Workbench FEA system.

  18. Enhanced Circular Dichroism of Gold Bilayered Slit Arrays Embedded with Rectangular Holes.

    Science.gov (United States)

    Zhang, Hao; Wang, Yongkai; Luo, Lina; Wang, Haiqing; Zhang, Zhongyue

    2017-01-01

    Gold bilayered slit arrays with rectangular holes embedded into the metal surface are designed to enhance the circular dichroism (CD) effect of gold bilayered slit arrays. The rectangular holes in these arrays block electric currents and generate localized surface plasmons around these holes, thereby strengthening the CD effect. The CD enhancement factor depends strongly on the rotational angle and the structural parameters of the rectangular holes; this factor can be enhanced further by drilling two additional rectangular holes into the metal surfaces of the arrays. These results help facilitate the design of chiral structures to produce a strong CD effect and large electric fields.

  19. The interference between two flat plates normal to a stream in staggered arrangement, 1

    International Nuclear Information System (INIS)

    Hirano, Kimitaka; Kawashima, Akira; Ohsako, Hideyuki.

    1983-01-01

    The clarification of the mutual interference characteristics between the bodies with sharp corners, such as flat plates and rectangular prisms placed perpendicularly to flow, is a fundamental and important problem. But it has not yet been sufficiently clarified. In flat plates, the points of breaking away do not move, a large breaking away region is in the wake, and the thickness is very thin in the direction of main flow. Moreover, a moment arises around the center of flat plates. In this study, a new parameter expressing the influence of channel walls on a single flat plate in the measuring part of two-dimensional wind tunnel experiment was proposed. The change of steady drag coefficient and Strouhal number corresponding to the series and parallel arrangements of two plates was clarified, and the patterns of the mutual interference were classified by using the results of visualizing flow in a circulation tank together. By the experimental results in the widely changed staggered arrangements, the isodrag contour diagram and isomoment contour diagram were drawn, and the general characteristics of mutual interference related to steady drag and moment were clarified. The experimental setup and method and the results are reported. (Kako, I.)

  20. Flow Characteristics of Rectangular Underexpanded Impinging Jets

    Institute of Scientific and Technical Information of China (English)

    Minoru YAGA; Yoshio KINJO; Masumi TAMASHIRO; Kenyu OYAKAWA

    2006-01-01

    In this paper, the flow fields of underexpanded impinging jet issued from rectangular nozzles of aspect ratio 1,3 and 5 are numerically and experimentally studied. Two dimensional temperature and pressure distributions are measured by using infrared camera and the combination of a pressure scanning device and a stepping motor, respectively. The variation of the stagnation pressure on the impinging plate reveals that a hystcretic phenomenon exists during the increasing and decreasing of the pressure ratio for the aspect ratio of 3.0 and 5.0. It is also found that the nozzle of aspect ratio 1.0 caused the largest total pressure loss pc/p0 = 0.27 at the pressure ratio of p0/pb, = 6.5, where pc is the stagnation center pressure on the wall, p0 the upstream stagnation pressure, pb the ambient pressure. The other two nozzles showed that the pressure loss pc / p0=0.52 and 0.55 were achieved by the nozzles of the aspect ratio 3,0 and 5.0, respectively. The comparison between the calculations and experiments is fairly good, showing the three dimensional streamlines and structures of the shock waves in the jets. However, the hysteresis of the pressure variations observed in the experiments between the pressure ratio of 3.5 and 4.5 cannot be confirmed in the calculations.

  1. Manufacturing of a HCLL cooling plate mock up

    International Nuclear Information System (INIS)

    Rigal, E.; Dinechin, G. de; Rampal, G.; Laffont, G.; Cachon, L.

    2007-01-01

    The European DEMO blankets and associated Test Blanket Modules (TBM) are made of a set of components cooled by flowing helium at 80bar pressure. Hot Isostatic Pressing (HIP) is one of the very few processes that allow manufacturing such components exhibiting complex cooling channels. In HIP technology, the parts used to manufacture components with embedded channels are usually machined plates, blocks and tubes. Achievable geometries are limited in shape because it is not always possible to figure the channels by bent tubes. This occurs for example when channels present sharp turns, when the cross section of the channels is rectangular or when the rib between channels is so small that very thin tubes would be required. In these cases, bending is unpractical. The breeder unit cooling plates of the Helium Cooled Lithium Lead (HCLL) blanket have eight 4 x 4.5 mm parallel channels that run following a double U scheme. Turns are sharp and the wall thickness is small (1mm), so the manufacturing process described above cannot be used. An alternative process has been developed which has many advantages. It consists in machining grooves in a base plate, then closing the top of the grooves using thin welded strips, and finally adding a plate by HIP. There is then no need for the use of tubes with associated bending and deformation issues. The final component contains welds, but it must be stressed out that these potentially brittle zones do not connect the channels to the external surface because they are covered by the HIPed plate. Furthermore, the welds are homogenised during the HIP operation and further heat treatments. This paper describes the design of a simplified cooling plate mock up and its fabrication using this so-called weld+HIP process. The thermal fatigue testing of this mock up is presented somewhere else in this conference. (orig.)

  2. On Mathematical Optimization for the Visualization of Frequencies and Adjacencies as Rectangular Maps

    DEFF Research Database (Denmark)

    Carrizosa, Emilio; Guerrero, Vanesa; Morales, Dolores Romero

    2018-01-01

    individuals as adjacent rectangular portions as possible and adding as few false adjacencies, i.e., adjacencies between rectangular portions corresponding to non-adjacent individuals, as possible. We formulate this visualization problem as a Mixed Integer Linear Programming (MILP) model. We propose......In this paper we address the problem of visualizing a frequency distribution and an adjacency relation attached to a set of individuals. We represent this information using a rectangular map, i.e., a subdivision of a rectangle into rectangular portions so that each portion is associated with one...

  3. Analysis of junior high school students' difficulty in resolving rectangular conceptual problems

    Science.gov (United States)

    Utami, Aliksia Kristiana Dwi; Mardiyana, Pramudya, Ikrar

    2017-08-01

    Geometry is one part of the mathematics that must be learned in school and it has important effects on the development of creative thinking skills of learners, but in fact, there are some difficulties experienced by the students. This research focuses on analysis difficulty in resolving rectangular conceptual problems among junior high school students in every creative thinking skills level. This research used a descriptive method aimed to identify the difficulties and cause of the difficulties experienced by five students. The difficulties are associated with rectangular shapes and related problems. Data collection was done based on students' work through test, interview, and observations. The result revealed that student' difficulties in understanding the rectangular concept can be found at every creative thinking skills level. The difficulties are identifying the objects rectangular in the daily life except for a rectangle and square, analyzing the properties of rectangular shapes, and seeing the interrelationships between figures.

  4. Experiences with rectangular waveguide

    International Nuclear Information System (INIS)

    Beltran, J.; Sepulveda, J. J.; Navarro, E. A.

    2000-01-01

    A simple and didactic experimental arrangement is presented to show wave propagation along a structure with translational symmetry, particularly the rectangular waveguide. Parameters of this waveguide as cutoff frequency, guide wavelength and field distribution of fundamental mode can be measured. For this purpose a large paralelepipedical waveguide structure is designed and built, its dimensions can be varied in order to change its parameters. (Author) 9 refs

  5. Experimental investigation on carbon nano tubes coated brass rectangular extended surfaces

    International Nuclear Information System (INIS)

    Senthilkumar, Rajendran; Prabhu, Sethuramalingam; Cheralathan, Marimuthu

    2013-01-01

    Finned surface has been extensively used for free convection cooling of internal combustion engines and several electronic kits etc. Here rectangular brass fin was preferred for analysis. Thermocouples were attached all over the surface of the fin in equal distances. The measurement of surface temperature and calculated convective heat transfer rate were reported for several heat input values. The overall system performance can be improved by enhancing heat transfer rate of extended surfaces. Based on the above requirement, brass surface was coated by carbon nano tubes. The temperature and heat transfer characteristics were investigated using Taguchi method for experimental design. Finally the performances of coated and non-coated rectangular brass fins were compared. The average percentage of increase in heat transfer rate was proved around 12% for carbon nanocoated rectangular brass fins. - Graphical abstract: The designed Natural and Forced convection Heat Transfer Test Rig measures the enhanced rate of heat transfer for nano coated rectangular fins than in non-coated fins. Highlights: ► Rectangular brass fins were preferred for convective heat transfer process. ► The rectangular brass fins are coated with multi wall carbon nano tubes in EBPVD process with nanometer thickness. ► Temperature and heat transfer rate were investigated for nanocoated and non-coated fins by using Taguchi method. ► Multi wall carbon nanotubes act as a pin fin to enhance surface area for effective convective heat transfer rate.

  6. Equivalent properties for perforated plates. An analytical approach

    International Nuclear Information System (INIS)

    Cepkauskas, M.M.; Yang Jianfeng

    2005-01-01

    Structures that contain perforated plates have been a subject of interest in the Nuclear Industry. Steam generators, condensers and reactor internals utilize plates containing holes which act as flow holes or separate structures from flow by using a 'tube bank' design. The equivalent plate method has been beneficial in analyzing perforate plates. Details are found in various papers found in the bibliography. In addition the ASME code addresses perforated plates in Appendix A-8000, but is limited to a triangular hole pattern. This early work performed in this field utilized test data and analytical approaches. This paper is an examination of an analytical approach for determining equivalent plate mechanical and thermal properties. First a patch of the real plate is identified that provides a model for the necessary physical behavior of the plate. The average strain of this patch is obtained by first applying simplified one dimensional mechanical load to the patch, determining stress as a function of position, converting the stress to strain and then integrating the strain over the patch length. This average strain is then equated to the average strain of an equivalent fictitious rectangular patch. This results in obtaining equivalent Young's Modulus and Poison's Ratio for the equivalent plate in all three orthogonal directions. The corresponding equivalent shear modulus in all three directions is then determined. An orthotropic material stress strain matrix relationship is provided for the fictitious properties. By equating the real average strain with the fictitious average strain in matrix form, a stress multiplier is found to convert average fictitious stress to average real stress. This same type of process is repeated for heat conduction coefficients and coefficients of thermal expansion. Results are provided for both a square and triangular hole pattern. Reasonable results are obtained when comparing the effective Young's Modulus and Poison's Ratio with ASME

  7. Optimal design for rectangular isolated footings using the real soil pressure

    Directory of Open Access Journals (Sweden)

    Arnulfo Luévanos Rojas

    2017-05-01

    Full Text Available The standard design method (classical method for reinforced concrete rectangular footings is: First, a dimension is proposed and should comply with the allowable stresses; subsequently, the effective depth is obtained from the maximum moment and is checked against the bending shear and the punching shear until, it complies with these conditions and, then, steel reinforcement is obtained, but it is not guarantee that the minimum cost will be obtained. This paper shows an optimal design for reinforced concrete rectangular footings using the new model. A numerical experimentation is presented to show the model capability to estimate the minimum cost design of the materials used for a rectangular footing that supports an axial load and moments in two directions in accordance to the building code requirements for structural concrete and commentary (ACI 318-13. Also, a comparison is made between the optimal design and current design for rectangular footings. The solutions show that the optimal design is more economical and more precise with respect to the current design, because standard design is done by trial and error. Then, the optimal design should be used to obtain the minimum cost design for reinforced concrete rectangular footings.

  8. Tau method approximation of the Hubbell rectangular source integral

    International Nuclear Information System (INIS)

    Kalla, S.L.; Khajah, H.G.

    2000-01-01

    The Tau method is applied to obtain expansions, in terms of Chebyshev polynomials, which approximate the Hubbell rectangular source integral:I(a,b)=∫ b 0 (1/(√(1+x 2 )) arctan(a/(√(1+x 2 )))) This integral corresponds to the response of an omni-directional radiation detector situated over a corner of a plane isotropic rectangular source. A discussion of the error in the Tau method approximation follows

  9. A new metamaterial-based wideband rectangular invisibility cloak

    Science.gov (United States)

    Islam, S. S.; Hasan, M. M.; Faruque, M. R. I.

    2018-02-01

    A new metamaterial-based wideband electromagnetic rectangular cloak is being introduced in this study. The metamaterial unit cell shows sharp transmittances in the C- and X-bands and displays wideband negative effective permittivity region there. The metamaterial unit cell was then applied in designing a rectangular-shaped electromagnetic cloak. The scattering reduction technique was adopted for the cloaking operation. The cloak operates in the certain portion of C-and X-bands that covers more than 4 GHz bandwidth region. The experimental results were provided as well for the metamaterial and the cloak.

  10. Thermal and hydrodynamic characteristics of forced and mixed convection flow through vertical rectangular channels

    Directory of Open Access Journals (Sweden)

    Hanafi Abdalla S.

    2008-01-01

    Full Text Available This paper presents experimental and numerical studies for the case of turbulent forced and mixed convection flow of water through narrow vertical rectangular channel. The channel is composed of two parallel plates which are heated at a uniform heat flux, whereas, the other two sides of the channel are thermally insulated. The plates are of 64 mm in width, 800 mm in height, and separated from each other at a narrow gap of 2.7 mm. The Nusselt number distribution along the flow direction normalized by the Nusselt number for the case of turbulent forced convection flow is obtained experimentally with a comparison with the numerical results obtained from a commercial computer code. The quantitative determination of the nor- malized Nusselt number with respect to the dimension-less number Z = (Gr/Re21/8Pr0.5 is presented with a comparison with previous experimental results. Qualitative results are presented for the normalized temperature and velocity profiles in the transverse direction with a comparison between the forced and mixed convection flow for both the cases of upward and downward flow directions. The effect of the axial locations and the parameter Gr/Re on the variation of the normalized temperature profiles in the transverse direction for both the regions of forced and mixed convection and for both of the upward and downward flow directions are obtained. The normalized velocity profiles in the transverse directions are also determined at different inlet velocity and heat fluxes for the previous cases. It is found that the normalized Nusselt number is greater than one in the mixed convection region for both the cases of upward and downward flow and correlated well with the dimension-less parameter Z for both of the forced and mixed convection regions. The temperature profiles increase with increasing the axial location along the flow direction or the parameter Gr/Re for both of the forced and mixed convection regions, but this increase is

  11. Thermal and stress analyses in thermoelectric generator with tapered and rectangular pin configurations

    International Nuclear Information System (INIS)

    Yilbas, Bekir Sami; Akhtar, S.S.; Sahin, A.Z.

    2016-01-01

    Thermal stress developed in thermoelectric generators is critical for long service applications. High temperature gradients, due to a large temperature difference across the junctions, causes excessive stress levels developed in the device pins and electrodes at the interfaces. In the present study, a thermoelectric generator with horizontal pin configuration is considered and thermal stress analysis in the device is presented. Ceramic wafer is considered to resemble the high temperature plate and copper electrodes are introduced at the pin junctions to reduce the electrical resistance between the pins and the high and low temperature junction plates during the operation. Finite element code is used to simulate temperature and stress fields in the thermoelectric generator. In the simulations, convection and radiation losses from the thermoelectric pins are considered and bismuth telluride pin material with and without tapering is incorporated. It is found that von Mises stress attains high values at the interface between the hot and cold junctions and the copper electrodes. Thermal stress developed in tapered pin configuration attains lower values than that of rectangular pin cross-section. - Highlights: • Different cold junction temperatures improves thermoelectric generator performance. • von Mises stress remains high across copper electrodes and hot junction ceramics. • von Mises stress reduces along pin length towards cold junction. • Pin tapering lowers stress levels in thermoelectric generator.

  12. On Hubbell's rectangular source integral

    International Nuclear Information System (INIS)

    Stalker, John

    2001-01-01

    The integral H(a,b)=∫ 0 b ∫ 0 a dx dy/(1+x 2 +y 2 ) arises naturally in the study of radiation from a rectangular source and has been studied by many authors. This paper introduces a new series expansion which is rapidly convergent for large a and b

  13. Analysis of the rectangular resonator with butterfly MMI coupler using SOI

    Science.gov (United States)

    Kim, Sun-Ho; Park, Jun-Hee; Kim, Eudum; Jeon, Su-Jin; Kim, Ji-Hoon; Choi, Young-Wan

    2018-02-01

    We propose a rectangular resonator sensor structure with butterfly MMI coupler using SOI. It consists of the rectangular resonator, total internal reflection (TIR) mirror, and the butterfly MMI coupler. The rectangular resonator is expected to be used as bio and chemical sensors because of the advantages of using MMI coupler and the absence of bending loss unlike ring resonators. The butterfly MMI coupler can miniaturize the device compared to conventional MMI by using a linear butterfly shape instead of a square in the MMI part. The width, height, and slab height of the rib type waveguide are designed to be 1.5 μm, 1.5 μm, and 0.9 μm, respectively. This structure is designed as a single mode. When designing a TIR mirror, we considered the Goos-Hänchen shift and critical angle. We designed 3:1 MMI coupler because rectangular resonator has no bending loss. The width of MMI is designed to be 4.5 μm and we optimize the length of the butterfly MMI coupler using finite-difference time-domain (FDTD) method for higher Q-factor. It has the equal performance with conventional MMI even though the length is reduced by 1/3. As a result of the simulation, Qfactor of rectangular resonator can be obtained as 7381.

  14. Rectangular superpolynomials for the figure-eight knot 41

    Science.gov (United States)

    Kononov, Ya. A.; Morozov, A. Yu.

    2017-11-01

    We rewrite the recently proposed differential expansion formula for HOMFLY polynomials of the knot 41 in an arbitrary rectangular representation R = [rs] as a sum over all Young subdiagrams λ of R with surprisingly simple coefficients of the Z factors. Intriguingly, these coefficients are constructed from the quantum dimensions of symmetric representations of the groups SL(r) and SL(s) and restrict the summation to diagrams with no more than s rows and r columns. Moreover, the β-deformation to Macdonald dimensions yields polynomials with positive integer coefficients, which are plausible candidates for the role of superpolynomials for rectangular representations. Both the polynomiality and the positivity of the coefficients are nonobvious, nevertheless true. This generalizes the previously known formulas for symmetric representations to arbitrary rectangular representations. The differential expansion allows introducing additional gradings. For the trefoil knot 31, to which our results for the knot 41 are immediately extended, we obtain the so-called fourth grading of hyperpolynomials. The property of factorization in roots of unity is preserved even in the five-graded case.

  15. Azimuthal critical heat flux in narrow rectangular channels

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yong Hoon; Noh, Sang Woo; Kim, Sung Joong; Suh, Kune Y. [Seoul National University, Seoul (Korea, Republic of)

    2003-07-01

    Tests were conducted to examine the critical heat flux (CHF) on the one-dimensional downward heating rectangular channel having a narrow gap by changing the orientation of the copper test heater assembly in a pool of saturated water under the atmospheric pressure. The test parameters include both the gap sizes of 1, 2, 5 and 10mm, and the surface orientation angles from the downward-facing position (180{sup o}) to the vertical position (90{sup o}), respectively. Also, the CHF experiments were performed for pool boiling with varying heater surface orientations in the unconfined space at the atmospheric pressure using the rectangular test section. It was observed that the CHF generally decreases as the surface inclination angle increases and as the gap size decreases. In consistency with several studies reported in the literature, it was found that there exists a transition angle above which the CHF changes with a rapid slope. An engineering correlation is developed for the CHF during natural convective boiling in the inclined, confined rectangular channels with the aid of dimensional analysis.

  16. Applicability of Modified Drift Flux Model for Bubbly Flow in 2-D/3-D Rectangular Box With Various Kinds of Obstacles

    International Nuclear Information System (INIS)

    Tatsuya Matsumoto; Akihiro Uchibori; Ryo Akasaka; Toshinori Seki; Shyuji Kaminishi; Koji Morita; Kenji Fukuda

    2002-01-01

    In order to develop analytical tools for the analyses of multi dimensional two-phase flow in channels with obstacles, the modified drift flux model has been applied. Numerical simulations of multi dimensional gas-liquid two-phase flow in a channel, with some kinds of obstacles inserted to simulate a simple sub-channel in the fuel bundle, were carried out. Analytical results were compared with experiments, to show the validity of the modified drift flux model. Experiments were carried out with using an apparatus of 2-D/3-D rectangular box with a perforated plate or a horizontal plate with slit hole or a vertical rod inserted. Nitrogen gas-water adiabatic two phase flow was circulated in the box. The apparatus was made of acrylic resin plates and be able to make the flow inside visualized. Two-phase flow pattern were recorded with a high-speed video camera and the mass flow rate of nitrogen gas was measured with a digital gas-mass flow meter. Comparisons between the experimental results and the numerical ones showed good agreements, thus it was verified the model would be applied for predicting flows in more complex geometry with obstacles. (authors)

  17. Characterization of counter-rotating streamwise vortices in flat rectangular channel with one-sided wavy wall

    KAUST Repository

    Bouremel, Yann

    2016-11-01

    Particle Image Velocimetry (PIV) has been used to characterize the evolution of counter-rotating streamwise vortices in a rectangular channel with one sided wavy surface. The vortices were created by a uniform set of saw-tooth carved over the leading edge of a flat plate at the entrance of a flat rectangular channel with one-sided wavy wall. PIV measurements were taken over the spanwise and streamwise planes at different locations and at Reynolds number of 2500. Two other Reynolds numbers of 2885 and 3333 have also been considered for quantification purpose. Pairs of counter-rotating streamwise vortices have been shown experimentally to be centred along the spanwise direction at the saw-tooth valley where the vorticity ωz=0ωz=0. It has also been found that the vorticity ωzωz of the pairs of counter-rotating vortices decreases along the streamwise direction, and increases with the Reynolds number. Moreover, different quantifications of such counter-rotating vortices have been discussed such as their size, boundary layer, velocity profile and vorticity. The current study shows that the mixing due to the wall shear stress of counter-rotating streamwise vortices as well as their averaged viscous dissipation rate of kinetic energy decrease over flat and adverse pressure gradient surfaces while increasing over favourable pressure gradient surfaces. Finally, it was also demonstrated that the main direction of stretching is orientated at around 45° with the main flow direction.

  18. Characterization of counter-rotating streamwise vortices in flat rectangular channel with one-sided wavy wall

    KAUST Repository

    Bouremel, Yann; Mitsudharmadi, Hatsari; Budiman, Alexander C.; Winoto, Sonny H.

    2016-01-01

    Particle Image Velocimetry (PIV) has been used to characterize the evolution of counter-rotating streamwise vortices in a rectangular channel with one sided wavy surface. The vortices were created by a uniform set of saw-tooth carved over the leading edge of a flat plate at the entrance of a flat rectangular channel with one-sided wavy wall. PIV measurements were taken over the spanwise and streamwise planes at different locations and at Reynolds number of 2500. Two other Reynolds numbers of 2885 and 3333 have also been considered for quantification purpose. Pairs of counter-rotating streamwise vortices have been shown experimentally to be centred along the spanwise direction at the saw-tooth valley where the vorticity ωz=0ωz=0. It has also been found that the vorticity ωzωz of the pairs of counter-rotating vortices decreases along the streamwise direction, and increases with the Reynolds number. Moreover, different quantifications of such counter-rotating vortices have been discussed such as their size, boundary layer, velocity profile and vorticity. The current study shows that the mixing due to the wall shear stress of counter-rotating streamwise vortices as well as their averaged viscous dissipation rate of kinetic energy decrease over flat and adverse pressure gradient surfaces while increasing over favourable pressure gradient surfaces. Finally, it was also demonstrated that the main direction of stretching is orientated at around 45° with the main flow direction.

  19. Joining of Aluminium Alloy Sheets by Rectangular Mechanical Clinching

    International Nuclear Information System (INIS)

    Abe, Y.; Mori, K.; Kato, T.

    2011-01-01

    A mechanical clinching has the advantage of low running costs. However, the joint strength is not high. To improve the maximum load of the joined sheets by a mechanical clinching, square and rectangular mechanical clinching were introduced. In the mechanical clinching, the two sheets are mechanically joined by forming an interlock between the lower and upper sheets by the punch and die. The joined length with the interlock was increased by the rectangular punch and die. The deforming behaviours of the sheets in the mechanical clinching were investigated, and then the interlock in the sheets had distribution in the circumference of the projection. Although the interlocks were formed in both projection side and diagonal, the interlock in the diagonal was smaller because of the long contact length between the lower sheet and the die cavity surface. The maximum load of the joined sheets by the rectangular mechanical clinching was two times larger than the load by the round mechanical clinching.

  20. 77 FR 3497 - Light-Walled Rectangular Pipe and Tube From Taiwan

    Science.gov (United States)

    2012-01-24

    ... Rectangular Pipe and Tube From Taiwan Determination On the basis of the record \\1\\ developed in the subject... order on light-walled rectangular pipe and tube from Taiwan would be likely to lead to continuation or recurrence of material injury to an industry in the United States within a reasonably foreseeable time. \\1...

  1. Perron-Frobenius Theorem for Rectangular Tensors and Directed Hypergraphs

    OpenAIRE

    Lu, Linyuan; Yang, Arthur L. B.; Zhao, James J. Y.

    2018-01-01

    For any positive integers $r$, $s$, $m$, $n$, an $(r,s)$-order $(n,m)$-dimensional rectangular tensor ${\\cal A}=(a_{i_1\\cdots i_r}^{j_1\\cdots j_s}) \\in ({\\mathbb R}^n)^r\\times ({\\mathbb R}^m)^s$ is called partially symmetric if it is invariant under any permutation on the lower $r$ indexes and any permutation on the upper $s$ indexes. Such partially symmetric rectangular tensor arises naturally in studying directed hypergraphs. Ling and Qi [Front. Math. China, 2013] first studied the $(p,q)$-...

  2. Augmented Beta rectangular regression models: A Bayesian perspective.

    Science.gov (United States)

    Wang, Jue; Luo, Sheng

    2016-01-01

    Mixed effects Beta regression models based on Beta distributions have been widely used to analyze longitudinal percentage or proportional data ranging between zero and one. However, Beta distributions are not flexible to extreme outliers or excessive events around tail areas, and they do not account for the presence of the boundary values zeros and ones because these values are not in the support of the Beta distributions. To address these issues, we propose a mixed effects model using Beta rectangular distribution and augment it with the probabilities of zero and one. We conduct extensive simulation studies to assess the performance of mixed effects models based on both the Beta and Beta rectangular distributions under various scenarios. The simulation studies suggest that the regression models based on Beta rectangular distributions improve the accuracy of parameter estimates in the presence of outliers and heavy tails. The proposed models are applied to the motivating Neuroprotection Exploratory Trials in Parkinson's Disease (PD) Long-term Study-1 (LS-1 study, n = 1741), developed by The National Institute of Neurological Disorders and Stroke Exploratory Trials in Parkinson's Disease (NINDS NET-PD) network. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Experimental study on the effect of gap size to CCFL and CHF in a vertical of narrow rectangular channel during quenching process

    International Nuclear Information System (INIS)

    Juarsa, Mulya; Putra, Nandy; Septiadi, Wayan Nata; Antariksawan, Anhar Riza

    2014-01-01

    Highlights: • Quenching in narrow rectangular channel with gap sizes variation was investigated. • The mechanism of counter-current flow depends on gap sizes variation. • The results confirmed the existence of CCFL in narrow rectangular channels. • CHF and mass flux gradient in the quenching was about 0.22 times than steady state. • Modification of CHF and mass flow rate dimensionless correlation was established. - Abstract: The quenching process has become an important thermal management study to intensify the safety margin for the integrity of the reactor vessel under the core meltdown condition. The boiling heat transfer mechanism in the channel is one aspect that needs further examination. The present study aimed to investigate the effect of the differences in channel gap size to counter-current flow limitation (CCFL) and critical heat flux (CHF) during transient cooling in atmospheric pressure and quenching using two vertical plates with 1 mm, 2 mm, and 3 mm gap sizes and heated length of 1100 mm. The initial temperature of the plate was set at 600 °C. Cooling water mass flow rate and sib-cooled temperature were set at about 0.089 kg/s and 90 °C, respectively. Calculations were performed to obtain the CHF value through the boiling curve using transient temperature data. Non-dimensional correlations from other research study was used in this research. The influence of gap sizes on CCFL and CHF resulted in an increased value of CHF relative to gap size; additionally, the CHF for gap sizes of 2 mm and 3 mm increased about 34.4% and 140.5%, respectively, compared to the CHF for the 1 mm gap size. In this research, a curve map of the relationship between non-dimensional CHF and non-dimensional mass flux of water flowing downward shows that the correlation of this experimental study has a gradient number of about 0.22 similar to Mishima and Nishihara correlation. The results confirmed the existence of CCFL in the vertical narrow rectangular channels due

  4. Stress Concentration and Its Mitigation Techniques in Flat Plate with Singularities - A Critical Review

    Directory of Open Access Journals (Sweden)

    Shubhashish Sanyal

    2012-01-01

    Full Text Available A number of analytical, numerical & experimental techniques are available for the reduction of stress concentration factor around discontinuities. Using various techniques the SCF around different discontinuities in a rectangular plate made up of different materials under different loading conditions have been reported in literature. Mitigation of stress concentration around different types of discontinuity is also reported in literature. This paper is to present an analysis and overview of emerging techniques developed for analysis as well as mitigation of stress concentration. The proposed methods in literature are compared.

  5. Process for the manufacture of plates containing neutron poison from aluminium and aluminium alloys

    International Nuclear Information System (INIS)

    Bauer, G.; Pollmann, E.; Srostlik, P.

    1985-01-01

    A process for guaranteeing sub-critical arrangements of nuclear fuel in tranport and/or storage containers is described, in which a homogeneous distribution of neutron poison in the aluminium matrix is guaranteed. A homogeneous mixture of aluminium powder and neutron poison powder is produced, this is pressed into plates in several stages, dried and made into hollow aluminium profiles of rectangular cross-section. The open ends of the hollow profile are then closed and this is rolled to the required dimension at 470-500 0 C. (orig./HP) [de

  6. Acoustic emission source location in plates using wavelet analysis and cross time frequency spectrum.

    Science.gov (United States)

    Mostafapour, A; Davoodi, S; Ghareaghaji, M

    2014-12-01

    In this study, the theories of wavelet transform and cross-time frequency spectrum (CTFS) are used to locate AE source with frequency-varying wave velocity in plate-type structures. A rectangular array of four sensors is installed on the plate. When an impact is generated by an artificial AE source such as Hsu-Nielsen method of pencil lead breaking (PLB) at any position of the plate, the AE signals will be detected by four sensors at different times. By wavelet packet decomposition, a packet of signals with frequency range of 0.125-0.25MHz is selected. The CTFS is calculated by the short-time Fourier transform of the cross-correlation between considered packets captured by AE sensors. The time delay is calculated when the CTFS reaches the maximum value and the corresponding frequency is extracted per this maximum value. The resulting frequency is used to calculate the group velocity of wave velocity in combination with dispersive curve. The resulted locating error shows the high precision of proposed algorithm. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Metamaterial Embedded Wearable Rectangular Microstrip Patch Antenna

    Directory of Open Access Journals (Sweden)

    J. G. Joshi

    2012-01-01

    Full Text Available This paper presents an indigenous low-cost metamaterial embedded wearable rectangular microstrip patch antenna using polyester substrate for IEEE 802.11a WLAN applications. The proposed antenna resonates at 5.10 GHz with a bandwidth and gain of 97 MHz and 4.92 dBi, respectively. The electrical size of this antenna is 0.254λ×0.5λ. The slots are cut in rectangular patch to reduce the bending effect. This leads to mismatch the impedance at WLAN frequency band; hence, a metamaterial square SRR is embedded inside the slot. A prototype antenna has been fabricated and tested, and the measured results are presented in this paper. The simulated and measured results of the proposed antenna are found to be in good agreement. The bending effect on the performance of this antenna is experimentally verified.

  8. Analytical solutions of heat transfer for laminar flow in rectangular channels

    Directory of Open Access Journals (Sweden)

    Rybiński Witold

    2014-12-01

    Full Text Available The paper presents two analytical solutions namely for Fanning friction factor and for Nusselt number of fully developed laminar fluid flow in straight mini channels with rectangular cross-section. This type of channels is common in mini- and microchannel heat exchangers. Analytical formulae, both for velocity and temperature profiles, were obtained in the explicit form of two terms. The first term is an asymptotic solution of laminar flow between parallel plates. The second one is a rapidly convergent series. This series becomes zero as the cross-section aspect ratio goes to infinity. This clear mathematical form is also inherited by the formulae for friction factor and Nusselt number. As the boundary conditions for velocity and temperature profiles no-slip and peripherally constant temperature with axially constant heat flux were assumed (H1 type. The velocity profile is assumed to be independent of the temperature profile. The assumption of constant temperature at the channel’s perimeter is related to the asymptotic case of channel’s wall thermal resistance: infinite in the axial direction and zero in the peripheral one. It represents typical conditions in a minichannel heat exchanger made of metal.

  9. Recovery of the Dirac system from the rectangular Weyl matrix function

    International Nuclear Information System (INIS)

    Fritzsche, B; Kirstein, B; Roitberg, I Ya; Sakhnovich, A L

    2012-01-01

    Weyl theory for Dirac systems with rectangular matrix potentials is non-classical. The corresponding Weyl functions are rectangular matrix functions. Furthermore, they are non-expansive in the upper semi-plane. Inverse problems are studied for such Weyl functions, and some results are new even for the square Weyl functions. High-energy asymptotics of Weyl functions and Borg–Marchenko-type uniqueness results are derived too. (paper)

  10. An accurate higher order displacement model with shear and normal deformations effects for functionally graded plates

    Energy Technology Data Exchange (ETDEWEB)

    Jha, D.K., E-mail: dkjha@barc.gov.in [Civil Engineering Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Kant, Tarun [Department of Civil Engineering, Indian Institute of Technology Bombay, Powai, Mumbai 400 076 (India); Srinivas, K. [Civil Engineering Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Singh, R.K. [Reactor Safety Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India)

    2013-12-15

    Highlights: • We model through-thickness variation of material properties in functionally graded (FG) plates. • Effect of material grading index on deformations, stresses and natural frequency of FG plates is studied. • Effect of higher order terms in displacement models is studied for plate statics. • The benchmark solutions for the static analysis and free vibration of thick FG plates are presented. -- Abstract: Functionally graded materials (FGMs) are the potential candidates under consideration for designing the first wall of fusion reactors with a view to make best use of potential properties of available materials under severe thermo-mechanical loading conditions. A higher order shear and normal deformations plate theory is employed for stress and free vibration analyses of functionally graded (FG) elastic, rectangular, and simply (diaphragm) supported plates. Although FGMs are highly heterogeneous in nature, they are generally idealized as continua with mechanical properties changing smoothly with respect to spatial coordinates. The material properties of FG plates are assumed here to vary through thickness of plate in a continuous manner. Young's modulii and material densities are considered to be varying continuously in thickness direction according to volume fraction of constituents which are mathematically modeled here as exponential and power law functions. The effects of variation of material properties in terms of material gradation index on deformations, stresses and natural frequency of FG plates are investigated. The accuracy of present numerical solutions has been established with respect to exact three-dimensional (3D) elasticity solutions and the other models’ solutions available in literature.

  11. An accurate higher order displacement model with shear and normal deformations effects for functionally graded plates

    International Nuclear Information System (INIS)

    Jha, D.K.; Kant, Tarun; Srinivas, K.; Singh, R.K.

    2013-01-01

    Highlights: • We model through-thickness variation of material properties in functionally graded (FG) plates. • Effect of material grading index on deformations, stresses and natural frequency of FG plates is studied. • Effect of higher order terms in displacement models is studied for plate statics. • The benchmark solutions for the static analysis and free vibration of thick FG plates are presented. -- Abstract: Functionally graded materials (FGMs) are the potential candidates under consideration for designing the first wall of fusion reactors with a view to make best use of potential properties of available materials under severe thermo-mechanical loading conditions. A higher order shear and normal deformations plate theory is employed for stress and free vibration analyses of functionally graded (FG) elastic, rectangular, and simply (diaphragm) supported plates. Although FGMs are highly heterogeneous in nature, they are generally idealized as continua with mechanical properties changing smoothly with respect to spatial coordinates. The material properties of FG plates are assumed here to vary through thickness of plate in a continuous manner. Young's modulii and material densities are considered to be varying continuously in thickness direction according to volume fraction of constituents which are mathematically modeled here as exponential and power law functions. The effects of variation of material properties in terms of material gradation index on deformations, stresses and natural frequency of FG plates are investigated. The accuracy of present numerical solutions has been established with respect to exact three-dimensional (3D) elasticity solutions and the other models’ solutions available in literature

  12. Rectangular waveguide-to-coplanar waveguide transitions at U-band using e-plane probe and wire bonding

    DEFF Research Database (Denmark)

    Dong, Yunfeng; Johansen, Tom Keinicke; Zhurbenko, Vitaliy

    2016-01-01

    This paper presents rectangular waveguide-to-coplanar waveguide (CPW) transitions at U-band (40–60 GHz) using E-plane probe and wire bonding. The designs of CPWs based on quartz substrate with and without aluminum cover are explained. The single and double layer rectangular waveguide-to-CPW trans......This paper presents rectangular waveguide-to-coplanar waveguide (CPW) transitions at U-band (40–60 GHz) using E-plane probe and wire bonding. The designs of CPWs based on quartz substrate with and without aluminum cover are explained. The single and double layer rectangular waveguide......-to-CPW transitions using E-plane probe and wire bonding are designed. The proposed rectangular waveguide-to-CPW transition using wire bonding can provide 10 GHz bandwidth at U-band and does not require extra CPWs or connections between CPWs and chips. A single layer rectangular waveguide-to-CPW transition using E......-plane probe with aluminum package has been fabricated and measured to validate the proposed transitions. To the authors' best knowledge, this is the first time that a wire bonding is used as a probe for rectangular waveguide-to-CPW transition at U-band....

  13. One-dimensional nonlinear theory for rectangular helix traveling-wave tube

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Chengfang, E-mail: fchffchf@126.com; Zhao, Bo; Yang, Yudong; Ju, Yongfeng [Faculty of Electronic Information Engineering, Huaiyin Institute of Technology, Huai' an 223003 (China); Wei, Yanyu [School of Physical Electronics, University of Electronic and Technology of China, Chengdu 610054 (China)

    2016-08-15

    A 1-D nonlinear theory of a rectangular helix traveling-wave tube (TWT) interacting with a ribbon beam is presented in this paper. The RF field is modeled by a transmission line equivalent circuit, the ribbon beam is divided into a sequence of thin rectangular electron discs with the same cross section as the beam, and the charges are assumed to be uniformly distributed over these discs. Then a method of computing the space-charge field by solving Green's Function in the Cartesian Coordinate-system is fully described. Nonlinear partial differential equations for field amplitudes and Lorentz force equations for particles are solved numerically using the fourth-order Runge-Kutta technique. The tube's gain, output power, and efficiency of the above TWT are computed. The results show that increasing the cross section of the ribbon beam will improve a rectangular helix TWT's efficiency and reduce the saturated length.

  14. A global limit load solution for plates with surface cracks under combined end force and cross-thickness bending

    International Nuclear Information System (INIS)

    Lei Yuebao; Fox, Mike J.H.

    2011-01-01

    A global limit load solution for rectangular surface cracks in plates under combined end force and cross-thickness bending is derived, which allows any combination of positive/negative end force and positive/negative cross-thickness moment. The solution is based on the net-section plastic collapse concept and, therefore, gives limit load values based on the Tresca yielding criterion. Solutions for both cases with and without crack face contact are derived when whole or part of the crack is located in the compressive stress zone. From the solution, particular global limit load solutions for plates with extended surface cracks and through-thickness cracks under the same loading conditions are obtained. The solution is consistent with the limit load solution for surface cracks in plates under combined tension and positive bending due to Goodall and Webster and Lei when both the applied end force and bending moment are positive. The solution reduces to the limit load solution for plain plates under combined end force and cross-thickness bending when the crack vanishes. - Highlights: → A global limit load solution for plates with surface cracks in plates is derived. → Combined positive/negative end force and positive/negative cross-thickness moment are considered. → The solution is based on the net-section plastic collapse concept.

  15. Full title: Biomechanical comparison between stainless steel, titanium and carbon-fiber reinforced polyetheretherketone volar locking plates for distal radius fractures.

    Science.gov (United States)

    Mugnai, Raffaele; Tarallo, Luigi; Capra, Francesco; Catani, Fabio

    2018-05-25

    As the popularity of volar locked plate fixation for distal radius fractures has increased, so have the number and variety of implants, including variations in plate design, the size and angle of the screws, the locking screw mechanism, and the material of the plates. carbon-fiber reinforced polyetheretherketone (CFR-PEEK) plate features similar biomechanical properties to metallic plates, representing, therefore, an optimal alternative for the treatment of distal radius fractures. three different materials-composed plates were evaluated: stainless steel volar lateral column (Zimmer); titanium DVR (Hand Innovations); CFR-PEEK DiPHOS-RM (Lima Corporate). Six plates for each type were implanted in sawbones and an extra-articular rectangular osteotomy was created. Three plates for each material were tested for load to failure and bending stiffness in axial compression. Moreover, 3 constructs for each plate were evaluated after dynamically loading for 6000 cycles of fatigue. the mean bending stiffness pre-fatigue was significantly higher for the stainless steel plate. The titanium plate yielded the higher load to failure both pre and post fatigue. After cyclic loading, the bending stiffness increased by a mean of 24% for the stainless steel plate; 33% for the titanium; and 17% for the CFR-PEEK plate. The mean load to failure post-fatigue increased by a mean of 10% for the stainless steel and 14% for CFR-PEEK plates, whereas it decreased (-16%) for the titanium plate. Statistical analysis between groups reported significant values (p plastic deformation, and lower load to failure. N/A. Copyright © 2018. Published by Elsevier Masson SAS.

  16. A modal approach to piano soundboard vibroacoustic behavior.

    Science.gov (United States)

    Trévisan, Benjamin; Ege, Kerem; Laulagnet, Bernard

    2017-02-01

    This paper presents an analytical method for modeling the vibro-acoustic behavior of ribbed non-rectangular orthotropic clamped plates. To do this, the non-rectangular plate is embedded in an extended rectangular simply supported plate on which a spring distribution is added, blocking the extended part of the surface, and allowing the description of any inner surface shapes. The acoustical radiation of the embedded plate is ensured using the radiation impedances of the extended rectangular simply supported plate. This method is applied to an upright piano soundboard: a non-rectangular orthotropic plate ribbed in both directions by several straight stiffeners. A modal decomposition is adopted on the basis of the rectangular extended simply supported plate modes, making it possible to calculate the modes of a piano soundboard in the frequency range [0;3000] Hz, showing the different associated mode families. Likewise, the acoustical radiation is calculated using the radiation impedances of a simply supported baffled plate, demonstrating the influence of the string coupling point positions on the acoustic radiated power. The paper ends with the introduction of indicators taking into account spatial and spectral variations of the excitation depending on the notes, which add to the accuracy of the study from the musical standpoint. A parametrical study, which includes several variations of soundboard design, highlights the complexity of rendering high-pitched notes homogeneous.

  17. Experimental and numerical investigation of flow field and heat transfer from electronic components in a rectangular channel with an impinging jet

    Directory of Open Access Journals (Sweden)

    Calisir Tamer

    2015-01-01

    Full Text Available Thermal control of electronic components is a continuously emerging problem as power loads keep increasing. The present study is mainly focused on experimental and numerical investigation of impinging jet cooling of 18 (3 × 6 array flash mounted electronic components under a constant heat flux condition inside a rectangular channel in which air, following impingement, is forced to exit in a single direction along the channel formed by the jet orifice plate and impingement plate. Copper blocks represent heat dissipating electronic components. Inlet flow velocities to the channel were measured by using a Laser Doppler Anemometer (LDA system. Flow field observations were performed using a Particle Image Velocimetry (PIV and thermocouples were used for temperature measurements. Experiments and simulations were conducted for Re = 4000 – 8000 at fixed value of H = 10 × Dh. Flow field results were presented and heat transfer results were interpreted using the flow measurement observations. Numerical results were validated with experimental data and it was observed that the results are in agreement with the experiments.

  18. A solution for the narrow rectangular punch

    NARCIS (Netherlands)

    Panek, C.F.; Kalker, J.J.

    1977-01-01

    This paper considers the problem of a rectangular flat ended punch acting on an elastic half-space. An approximate solution is generated through application of the elastic line integral equations. The results produced by this method are then compared with another approximate solution already

  19. Vibration analysis of concrete bridges during a train pass-by using various models

    International Nuclear Information System (INIS)

    Li, Qi; Wang, Ke; Cheng, Shili; Li, Wuqian; Song, Xiaodong

    2016-01-01

    The vibration of a bridge must be determined in order to predict the bridge noise during a train pass-by. It can be generally solved with different models either in the time domain or the frequency domain. The computation cost and accuracy of these models vary a lot in a wide frequency band. This study aims to compare the results obtained from various models for recommending the most suitable model in further noise prediction. First, train-track-bridge models in the time domain are developed by using the finite element method and mode superposition method. The rails are modeled by Timoshenko beam elements and the bridge is respectively modeled by shell elements and volume elements. Second, power flow models for the coupled system are established in the frequency domain. The rails are modelled by infinite Timoshenko beams and the bridge is respectively represented by three finite element models, an infinite Kirchhoff plate, and an infinite Mindlin plate model. The vibration at given locations of the bridge and the power input to the bridges through the rail fasteners are calculated using these models. The results show that the shear deformation of the bridge deck has significant influences on the bridge vibration at medium-to-high frequencies. The Mindlin plate model can be used to represent the U-shaped girder to obtain the power input to the bridge with high accuracy and efficiency. (paper)

  20. Solving the rectangular assignment problem and applications

    NARCIS (Netherlands)

    Bijsterbosch, J.; Volgenant, A.

    2010-01-01

    The rectangular assignment problem is a generalization of the linear assignment problem (LAP): one wants to assign a number of persons to a smaller number of jobs, minimizing the total corresponding costs. Applications are, e.g., in the fields of object recognition and scheduling. Further, we show

  1. DNB Mechanistic model assessment based on experimental data in narrow rectangular channel

    International Nuclear Information System (INIS)

    Zhou Lei; Yan Xiao; Huang Yanping; Xiao Zejun; Huang Shanfang

    2011-01-01

    The departure from nuclear boiling (DNB) is important concerning about the safety of a PWR. Lacking assessment by experimental data points, it's doubtful whether the existing models can be used in narrow rectangular channels or not. Based on experimental data points in narrow rectangular channels, two kinds of classical DNB models, which include liquid sublayer dryout model (LSDM) and bubble crowding model (BCM), were assessed. The results show that the BCM has much wider application range than the LSDM. Several thermal parameters show systematical influences on the calculated results by the models. The performances of all the models deteriorate as the void fraction increases. The reason may be attributed to the geometrical differences between a circular tube and narrow rectangular channel. (authors)

  2. Rectangular spectral collocation

    KAUST Repository

    Driscoll, Tobin A.

    2015-02-06

    Boundary conditions in spectral collocation methods are typically imposed by removing some rows of the discretized differential operator and replacing them with others that enforce the required conditions at the boundary. A new approach based upon resampling differentiated polynomials into a lower-degree subspace makes differentiation matrices, and operators built from them, rectangular without any row deletions. Then, boundary and interface conditions can be adjoined to yield a square system. The resulting method is both flexible and robust, and avoids ambiguities that arise when applying the classical row deletion method outside of two-point scalar boundary-value problems. The new method is the basis for ordinary differential equation solutions in Chebfun software, and is demonstrated for a variety of boundary-value, eigenvalue and time-dependent problems.

  3. Propellant Feed System for Swirl-Coaxial Injection

    Science.gov (United States)

    Reynolds, David Christopher (Inventor)

    2015-01-01

    A propellant feed system for swirl-coaxial injection of a liquid propellant includes a reservoir having a bottom plate and at least one tube originating in the bottom plate and extending therefrom. The tube has rectangular slits defined in and distributed tangentially and evenly about a portion of the tube that is disposed in the bottom plate. Drain holes are provided in the bottom plate and tunnels are defined in the bottom plate. Each tunnel fluidly couples one of the drain holes to a corresponding one of the rectangular slits. Each tunnel includes (i) a bend of at least 90.degree., and (ii) a straight portion leading to its corresponding rectangular slit wherein the straight portion is at least five times as long as a hydraulic diameter of the corresponding rectangular slit.

  4. A fixed point theorem for uniformly locally contractive mappings in a C-chainable cone rectangular metric space

    Directory of Open Access Journals (Sweden)

    Bessem Samet

    2011-09-01

    Full Text Available Recently, Azam, Arshad and Beg [ Banach contraction principle on cone rectangular metric spaces, Appl. Anal. Discrete Math. 2009] introduced the notion of cone rectangular metric spaces by replacing the triangular inequality of a cone metric space by a rectangular inequality. In this paper, we introduce the notion of c-chainable cone rectangular metric space and we establish a fixed point theorem for uniformly locally contractive mappings in such spaces. An example is given to illustrate our obtained result.

  5. Various methods of determining the natural frequencies and damping of composite cantilever plates. 3. The Ritz method

    Science.gov (United States)

    Ekel'chik, V. S.; Ryabov, V. M.

    1997-03-01

    The Ritz method was used to determine the frequencies and forms of free vibrations of rectangular cantilever plates made of anisotropic laminated composites. Orthogonal Jacobi and Legendre polynomials were used as coordinate functions. The results of the calculations are in good agreement with the published experimental and calculated data of other authors for plates made of boron and carbon fiber reinforced plastics with different angles of reinforcement of unidirectional layers and different sequence of placing the layers, and also of isotropic plates. The dissipative characteristics in vibrations were determined on the basis of the concept of complex moduli. The solution of the frequency equation with complex coefficients yields a complex frequency; the loss factors are determined from the ratio of the imaginary component of the complex frequency to the real component. For plates of unidirectionally reinforced carbon fiber plastic with different relative length a detailed analysis of the influence of the angle of reinforcement on the interaction and frequency transformation and on the loss factor was carried out. The article shows that the loss factor of a plate depends substantially on the type of vibration mode: bending or torsional. It also examines the asymptotics of the loss factors of plates when their length is increased, and it notes that the binomial model of deformation leads to a noticeable error in the calculation of the loss factor of long plates when the angle of reinforcement lies in the range 20°<φ<70°.

  6. Basic study on the rectangular numeric keys for touch screen.

    Science.gov (United States)

    Harada, H; Katsuura, T; Kikuchi, Y

    1997-06-01

    The present study was conducted to examine the optimum inter-key spacing of numeric rectangular keys for touch screens. Six male students (22-25 years old) and three female students (21-24 years old) participated in the experiment. Each subject performed the data entry task using rectangular keys of touch devices. These keys were arranged in both horizontal and vertical layouts. The sizes of the rectangular keys in both layouts were 12 x 21 mm and 15 x 39 mm, and each of the inter-key spacing of each key was 0, 3, 6, 12 and 21 mm. The response time with inter-key spacing of 3 mm was significantly faster than with the inter-key spacing of 0, 12 and 21 mm (p < 0.05). Keys of vertical position produced faster response time than that of horizontal position. The subjective ratings showed that the inter-key spacing of 6 mm was significantly better than the inter-key spacing of 0, 3, 12 and 21 mm (p < 0.05).

  7. A Multi-Objective Approach to Visualize Proportions and Similarities Between Individuals by Rectangular Maps

    DEFF Research Database (Denmark)

    Carrizosa, Emilio; Guerrero, Vanesa; Morales, Dolores Romero

    In this paper we address the problem of visualizing the proportions and the similarities attached to a set of individuals. We represent this information using a rectangular map, i.e., a subdivision of a rectangle into rectangular portions so that each portion is associated with one individual...... area and adjacency requirements, this visualization problem is formulated as a three-objective Mixed Integer Nonlinear Problem. The first objective seeks to maximize the number of true adjacencies that the rectangular map is able to reproduce, the second one is to minimize the number of false...

  8. Steady turbulent flow in curved rectangular channels

    NARCIS (Netherlands)

    De Vriend, H.J.

    1979-01-01

    After the study of fully developed and developing steady laminar flow in curved channels of shallow rectangular wet cross-section (see earlier reports in this series), steady turbulent flow in such channels is investigated as a next step towards a mathematical model of the flow in shallow river

  9. Studi Numerik Pengaruh Posisi Sudut Obstacle Berbentuk Rectangular Terhadap Perpindahan Panas pada Tube Banks Staggered

    Directory of Open Access Journals (Sweden)

    Rizki Anggiansyah

    2014-09-01

    Full Text Available Compact heat exchanger merupakan salah satu tipe dari alat penukar kalo (heat exchanger yang memiliki luasan perpindahan panas per unit volume yang paling besar (≥ 400 m2/m3 for liquids dan ≥ 700 m2/m3 for gases yang tersusun dari fin and tube. Dalam hal performa, compact heat exchanger bergantung pada pola permukaan fin, yakni continuous plate fins, wavy fins dan circular fins. Continuous plate fins memiliki pola permukaan fin yang datar dan hal tersebut mengakibatkan perpindahan panas yang terjadi relatif lebih lama dibandingkan tipe wavy fins dengan pola permukaan yang bergelombang. Selain merubah pola permukaan fin, upaya lain untuk bisa memaksimalkan proses perpindahan panas pada continuous plate fins juga dapat dibentuk dengan penambahan obstacle pada permukaannya. Penelitian ini dilakukan dengan metode simulasi numerik dengan menggunakan bantuan software Fluent 6.3.26. Simulasi ini dikondisikan dengan menggunakan model turbulensi k-epsilon RNG dan metode second-order upwind scheme. Pada penelitian ini yang divariasikan adalah posisi sudut dari obstacle berbentuk rectangular pada kemiringan 120o, 135o dan 150o berdasarkan titik pusat tube yang diukur dari stagnation point, dengan ukuran panjang obstacle tetap sebesar 2,5 mm dan lebar sebesar 0,5 mm pada tube banks yang tersusun secara staggered. Fluida kerja yang digunakan adalah udara yang dimodelkan sebagai gas ideal yang mengalir melintas celah antara tube dengan temperatur inlet 310 K dan temperatur tube konstan sebesar 347 K. Dari hasil simulasi ini didapatkan visualisasi kontur kecepatan, temperatur dan visualisasi pola aliran yang terbentuk serta pembuktian hipotesa bahwa dengan adanya penambahan obstacle akan meningkatkan perpindahan panas. yakni nilai Nusselt number 8,9–40,6%  sebesar terhadap model baseline (tanpa penambahan obstacle.

  10. Relativistic energy-dispersion relations of 2D rectangular lattices

    Science.gov (United States)

    Ata, Engin; Demirhan, Doğan; Büyükkılıç, Fevzi

    2017-04-01

    An exactly solvable relativistic approach based on inseparable periodic well potentials is developed to obtain energy-dispersion relations of spin states of a single-electron in two-dimensional (2D) rectangular lattices. Commutation of axes transfer matrices is exploited to find energy dependencies of the wave vector components. From the trace of the lattice transfer matrix, energy-dispersion relations of conductance and valence states are obtained in transcendental form. Graphical solutions of relativistic and nonrelativistic transcendental energy-dispersion relations are plotted to compare how lattice parameters V0, core and interstitial size of the rectangular lattice affects to the energy-band structures in a situation core and interstitial diagonals are of equal slope.

  11. 78 FR 42546 - Light-Walled Rectangular Pipe and Tube From China, Korea, Mexico, and Turkey: Notice of...

    Science.gov (United States)

    2013-07-16

    ...-Walled Rectangular Pipe and Tube From China, Korea, Mexico, and Turkey: Notice of Commission... countervailing duty order on light-walled rectangular pipe and tube from China and the antidumping duty orders on light-walled rectangular pipe and tube from China, Korea, Mexico, and Turkey would be likely to lead to...

  12. Electrical Machines: Turn-to-Turn Capacitance in Formed Windings with Rectangular Cross-Section Wire

    NARCIS (Netherlands)

    Djukic, Nenad; Encica, L.; Paulides, Johan

    2015-01-01

    Calculation of turn-to-turn capacitance (Ctt) in electrical machines (EMs) with formed windings with rectangular cross-section wire is presented. Three calculation methods are used for the calculation of Ctt in case of rectangular conductors – finite element (FE) method and two previously published

  13. Flow Through a Rectangular-to-Semiannular Diffusing Transition Duct

    Science.gov (United States)

    Foster, Jeff; Wendt, Bruce J.; Reichert, Bruce A.; Okiishi, Theodore H.

    1997-01-01

    Rectangular-to-semiannular diffusing transition ducts are critical inlet components on supersonic airplanes having bifucated engine inlets. This paper documents measured details of the flow through a rectangular-to-semiannular transition duct having an expansion area ratio of 1.53. Three-dimensional velocity vectors and total pressures at the exit plane of the diffuser are presented. Surface oil-flow visualization and surface static pressure data are shown. The tests were conducted with an inlet Mach number of 0.786 and a Reynolds number based on the inlet centerline velocity and exit diameter of 3.2 x 10(exp 6). The measured data are compared with previously published computational results. The ability of vortex generators to reduce circumferential total pressure distortion is demonstrated.

  14. PERFORMANCE ANALYSIS OF RECTANGULAR MPA USING DIFFERENT SUBSTRATE MATERIALS FOR WLAN APPLICATION

    Directory of Open Access Journals (Sweden)

    E Aravindraj

    2017-03-01

    Full Text Available In this paper, a rectangular microstrip patch antenna (MPA is designed using different substrate materials for analyzing the performance of the MPA. Alumina (Al2O3, Bakelite, Beryllium oxide (BeO, Gallium Arsenide (GaAs, RT-Duroid and Flame Retardant 4 (FR-4 are the six different substrate used in the design. The size of the rectangular microstrip patch antenna varies according to the dielectric constant of substrate materials used. The operating frequency taken for this analysis is 5.8 GHz. The proposed design provides the study on the performance of rectangular microstrip patch antenna for different substrate materials using the same frequency. This study conveys that which substrate material provides better performance. Moreover, this comparative study conveys that which substrate material provides better performance. The simulation parameters are investigated using HFSS.

  15. Research on applications of rectangular beam in micro laser propulsion

    International Nuclear Information System (INIS)

    Jiao, L.; Cai, J.; Ma, H.H.; Li, G.X.; Li, L.; Shen, Z.W.; Tang, Z.P.

    2014-01-01

    Highlights: • Diode laser bar of 808 nm is introduced into the micro laser propulsion field. • Double base propellant (DBP) coating with BOPP substrate was obtained. • The combination of laser power and energy decides the propulsion performance. • The new rectangular beam prefers to produce higher impulse. - Abstract: Micro laser propulsion is a new technology with brilliant future. In order to reduce the thruster mass and volume further, laser bar is introduced into the micro laser propulsion field. A new kind of 220 × 20 μm rectangular beam of 808 nm was obtained by oval lens compressing the light of diode at fast axes and slow axes. The effect of laser power, energy and coating thickness of double base propellant on propulsion performance was studied. Propulsion performance of double base propellant under static and dynamic mode shows some different characters. Compared to round beam, the new beam prefers to produce higher impulse. Ablation efficiency of DBP shows better performance in short laser duration. The combination of power density and energy density decides the laser propulsion performance. The new rectangular beam is appropriate for millisecond micro-laser propulsion

  16. Numerical study of the stress-strain state of reinforced plate on an elastic foundation by the Bubnov-Galerkin method

    Science.gov (United States)

    Beskopylny, Alexey; Kadomtseva, Elena; Strelnikov, Grigory

    2017-10-01

    The stress-strain state of a rectangular slab resting on an elastic foundation is considered. The slab material is isotropic. The slab has stiffening ribs that directed parallel to both sides of the plate. Solving equations are obtained for determining the deflection for various mechanical and geometric characteristics of the stiffening ribs which are parallel to different sides of the plate, having different rigidity for bending and torsion. The calculation scheme assumes an orthotropic slab having different cylindrical stiffness in two mutually perpendicular directions parallel to the reinforcing ribs. An elastic foundation is adopted by Winkler model. To determine the deflection the Bubnov-Galerkin method is used. The deflection is taken in the form of an expansion in a series with unknown coefficients by special polynomials, which are a combination of Legendre polynomials.

  17. 78 FR 74161 - Light-Walled Rectangular Pipe and Tube From China, Korea, Mexico, and Turkey; Scheduling of Full...

    Science.gov (United States)

    2013-12-10

    ...-Walled Rectangular Pipe and Tube From China, Korea, Mexico, and Turkey; Scheduling of Full Five-Year... the Antidumping Duty Orders on Light-Walled Rectangular Pipe and Tube From China, Korea, Mexico, and... on light- walled rectangular pipe and tube from China, Korea, Mexico, and Turkey would be likely to...

  18. Modeling on bubbly to churn flow pattern transition in narrow rectangular channel

    International Nuclear Information System (INIS)

    Wang Yanlin; Chen Bingde; Huang Yanping; Wang Junfeng

    2012-01-01

    A theoretical model based on some reasonable concepts was developed to predict the bubbly flow to churn flow pattern transition in vertical narrow rectangular channel under flow boiling condition. The maximum size of ideal bubble in narrow rectangular channel was calculated based on previous literature. The thermal hydraulics boundary condition of bubbly to churn flow pattern transition was exported from Helmholtz and maximum size of ideal bubble. The theoretical model was validated by existent experimental data. (authors)

  19. Entropy generation and thermodynamic analysis of solar air heaters with artificial roughness on absorber plate

    Directory of Open Access Journals (Sweden)

    Prasad Radha K.

    2017-09-01

    Full Text Available This paper presents mathematical modelling and numerical analysis to evaluate entropy generation analysis (EGA by considering pressure drop and second law efficiency based on thermodynamics for forced convection heat transfer in rectangular duct of a solar air heater with wire as artificial roughness in the form of arc shape geometry on the absorber plate. The investigation includes evaluations of entropy generation, entropy generation number, Bejan number and irreversibilities of roughened as well as smooth absorber plate solar air heaters to compare the relative performances. Furthermore, effects of various roughness parameters and operating parameters on entropy generation have also been investigated. Entropy generation and irreversibilities (exergy destroyed has its minimum value at relative roughness height of 0.0422 and relative angle of attack of 0.33, which leads to the maximum exergetic efficiency. Entropy generation and exergy based analyses can be adopted for the evaluation of the overall performance of solar air heaters.

  20. 75 FR 82070 - Light-Walled Rectangular Pipe and Tube From China, Korea, and Mexico

    Science.gov (United States)

    2010-12-29

    ...-Walled Rectangular Pipe and Tube From China, Korea, and Mexico AGENCY: United States International Trade... from China, Korea, and Mexico that were found to be sold at less than fair value. Nacional de Acero S... panel proceeding in Light-Walled Rectangular Pipe and Tube from Mexico, USA-MEX-1904-04, to file...

  1. The time of simultaneous tunneling of identical particles through the rectangular quantum barrier

    International Nuclear Information System (INIS)

    Martsenyuk, L.S.; Omelchenko, S.A.

    2010-01-01

    Work is devoted to studying the influence of exchange processes on a time of simultaneous crossing by identical particles of a rectangular quantum barrier. It is shown, that such processes essentially influence on the parameters of tunneling. The size of addition to time of identical particles tunneling, arising up because of their exchange interaction in a field of a rectangular quantum barrier is first counted.

  2. Vibrational response of a rectangular duct of finite length excited by a turbulent internal flow

    Science.gov (United States)

    David, Antoine; Hugues, Florian; Dauchez, Nicolas; Perrey-Debain, Emmanuel

    2018-05-01

    Gas transport ductwork in industrial plants or air conditioning networks can be subject to vibrations induced by the internal flow. Most studies in this matter have been carried out on circular ducts. This paper focuses specifically on the vibratory response of a rectangular duct of finite length excited by an internal turbulent flow. A semi-analytical model taking into account the modal response of the structure due to both aerodynamic and acoustic contributions is derived. The aerodynamic component of the excitation is applied on the basis of Corcos model where the power spectral density of the wall pressure is determined experimentally. The acoustic component is based on the propagating modes in the duct where the acoustic modal contribution are extracted via cross-spectral densities. The vibrational response is given for a 0.2 × 0.1 × 0.5 m3 duct made of 3 mm steel plates excited by 20 m/s or 30 m/s flows. Comparisons between experimental results and numerical predictions show a good agreement. The competition between acoustic and aerodynamic components is highlighted.

  3. Three Dimensional Parametric Analyses of Stress Concentration Factor and Its Mitigation in Isotropic and Orthotropic Plate with Central Circular Hole Under Axial In-Plane Loading

    Science.gov (United States)

    Nagpal, Shubhrata; Jain, Nitin Kumar; Sanyal, Shubhashis

    2016-01-01

    The problem of finding the stress concentration factor of a loaded rectangular plate has offered considerably analytical difficulty. The present work focused on understanding of behavior of isotropic and orthotropic plate subjected to static in-plane loading using finite element method. The complete plate model configuration has been analyzed using finite element method based software ANSYS. In the present work two parameters: thickness to width of plate (T/A) and diameter of hole to width of plate (D/A) have been varied for analysis of stress concentration factor (SCF) and its mitigation. Plates of five different materials have been considered for complete analysis to find out the sensitivity of stress concentration factor. The D/A ratio varied from 0.1 to 0.7 for analysis of SCF and varied from 0.1 to 0.5 for analyzing the mitigation of SCF. 0.01, 0.05 and 0.1 are considered as T/A ratio for all the cases. The results are presented in graphical form and discussed. The mitigation in SCF reported is very encouraging. The SCF is more sensitive to D/A ratio as compared to T/A.

  4. Graphene-based tunable terahertz filter with rectangular ring ...

    Indian Academy of Sciences (India)

    A plasmonic band-pass filter based on graphene rectangular ring resonator with double narrow gaps is proposed and numerically investigated by finite-difference time-domain (FDTD) simulations. For the filter with or without gaps, the resonant frequencies can be effectively adjusted by changing the width of the graphene ...

  5. Graphene-based tunable terahertz filter with rectangular ring ...

    Indian Academy of Sciences (India)

    WEI SU

    2017-08-16

    Aug 16, 2017 ... Abstract. A plasmonic band-pass filter based on graphene rectangular ring resonator with double narrow gaps is proposed and numerically investigated by finite-difference time-domain (FDTD) simulations. For the filter with or without gaps, the resonant frequencies can be effectively adjusted by changing ...

  6. Investigation of imaging properties for submillimeter rectangular pinholes

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Dan, E-mail: dxia@uchicago.edu [The Department of Radiology, The University of Chicago, Chicago, Illinois 60637 (United States); Moore, Stephen C., E-mail: scmoore@bwh.harvard.edu, E-mail: miaepark@bwh.harvard.edu, E-mail: mcervo@bwh.harvard.edu; Park, Mi-Ae, E-mail: scmoore@bwh.harvard.edu, E-mail: miaepark@bwh.harvard.edu, E-mail: mcervo@bwh.harvard.edu; Cervo, Morgan, E-mail: scmoore@bwh.harvard.edu, E-mail: miaepark@bwh.harvard.edu, E-mail: mcervo@bwh.harvard.edu [Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts 02115 (United States); Metzler, Scott D., E-mail: metzler@upenn.edu [The Department of Radiology, The University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States)

    2015-12-15

    Purpose: Recently, a multipinhole collimator with inserts that have both rectangular apertures and rectangular fields of view (FOVs) has been proposed for SPECT imaging since it can tile the projection onto the detector efficiently and the FOVs in transverse and axial directions become separable. The purpose of this study is to investigate the image properties of rectangular-aperture pinholes with submillimeter apertures sizes. Methods: In this work, the authors have conducted sensitivity and FOV experiments for 18 replicates of a prototype insert fabricated in platinum/iridium (Pt/Ir) alloy with submillimeter square-apertures. A sin{sup q}θ fit to the experimental sensitivity has been performed for these inserts. For the FOV measurement, the authors have proposed a new formula to calculate the projection intensity of a flood image on the detector, taking into account the penumbra effect. By fitting this formula to the measured projection data, the authors obtained the acceptance angles. Results: The mean (standard deviation) of fitted sensitivity exponents q and effective edge lengths w{sub e} were, respectively, 10.8 (1.8) and 0.38 mm (0.02 mm), which were close to the values, 7.84 and 0.396 mm, obtained from Monte Carlo calculations using the parameters of the designed inserts. For the FOV measurement, the mean (standard deviation) of the transverse and axial acceptances were 35.0° (1.2°) and 30.5° (1.6°), which are in good agreement with the designed values (34.3° and 29.9°). Conclusions: These results showed that the physical properties of the fabricated inserts with submillimeter aperture size matched our design well.

  7. Methodical Specifics of Thermal Experiments with Thin Carbon Reinforced Plates

    Directory of Open Access Journals (Sweden)

    O. V. Denisov

    2015-01-01

    Full Text Available Polymer composite materials (CM are widely used in creation of large space constructions, especially reflectors of space antennas. Composite materials should provide high level of specific stiffness and strength for space structures. Thermal conductivity in reinforcement plane is a significant factor in case of irregular heating space antennas. Nowadays, data on CM reinforcement plane thermal conductivity are limited and existing methods of its defining are imperfect. Basically, traditional methods allow us to define thermal conductivity in perpendicular direction towards the reinforcement plane on the samples of round or rectangular plate. In addition, the thickness of standard samples is larger than space antenna thickness. Consequently, new methods are required. Method of contact heating, which was developed by BMSTU specialists with long hollow carbon beam, could be a perspective way. This article is devoted to the experimental method of contact heating on the thin carbon plates.Thermal tests were supposed to provide a non-stationary temperature field with a gradient being co-directional with the plane reinforcement in the material sample. Experiments were conducted in vacuum chamber to prevent unstructured convection. Experimental thermo-grams processing were calculated by 1-d thermal model for a thin plate. Influence of uncertainty of experimental parameters, such as (radiation emission coefficients of sample surface, glue, temperature sensors and uncertainty of sensors placement on the result of defined thermal conductivity has been estimated. New data on the thermal conductivity in reinforcement plane were obtained within 295 - 375 K temperature range, which can be used to design and develop reflectors of precision space antennas. In the future it is expedient to conduct tests of thin-wall plates from carbon fiber-reinforced plastic in wide temperature range, especially in the low-range temperatures.

  8. Computational Investigations in Rectangular Convergent and Divergent Ribbed Channels

    Science.gov (United States)

    Sivakumar, Karthikeyan; Kulasekharan, N.; Natarajan, E.

    2018-05-01

    Computational investigations on the rib turbulated flow inside a convergent and divergent rectangular channel with square ribs of different rib heights and different Reynolds numbers (Re=20,000, 40,000 and 60,000). The ribs were arranged in a staggered fashion between the upper and lower surfaces of the test section. Computational investigations are carried out using computational fluid dynamic software ANSYS Fluent 14.0. Suitable solver settings like turbulence models were identified from the literature and the boundary conditions for the simulations on a solution of independent grid. Computations were carried out for both convergent and divergent channels with 0 (smooth duct), 1.5, 3, 6, 9 and 12 mm rib heights, to identify the ribbed channel with optimal performance, assessed using a thermo hydraulic performance parameter. The convergent and divergent rectangular channels show higher Nu values than the standard correlation values.

  9. Are Haar-like Rectangular Features for Biometric Recognition Reducible?

    DEFF Research Database (Denmark)

    Nasrollahi, Kamal; Moeslund, Thomas B.

    2013-01-01

    Biometric recognition is still a very difficult task in real-world scenarios wherein unforeseen changes in degradations factors like noise, occlusion, blurriness and illumination can drastically affect the extracted features from the biometric signals. Very recently Haar-like rectangular features...... which have usually been used for object detection were introduced for biometric recognition resulting in systems that are robust against most of the mentioned degradations [9]. The problem with these features is that one can define many different such features for a given biometric signal...... and it is not clear whether all of these features are required for the actual recognition or not. This is exactly what we are dealing with in this paper: How can an initial set of Haar-like rectangular features, that have been used for biometric recognition, be reduced to a set of most influential features...

  10. Effect of rising time of rectangular pulse on inactivation of staphylococcus aureus by pulsed electric field

    Science.gov (United States)

    Zhang, Ruobing; Liang, Dapeng; Zheng, Nanchen; Xiao, Jianfu; Mo, Mengbin; Li, Jing

    2013-03-01

    Pulsed electric field (PEF) is a novel non-thermal food processing technology that involves the electric discharge of high voltage short pulses through the food product. In PEF study, rectangular pulses are most commonly used for inactivating microorganisms. However, little information is available on the inactivation effect of rising time of rectangular pulse. In this paper, inactivation effects, electric field strength, treatment time and conductivity on staphylococcus aureus inactivation were investigated when the pulse rising time is reduced from 2.5 μs to 200 ns. Experimental results showed that inactivation effect of PEF increased with electric field strength, solution conductivity and treatment time. Rising time of the rectangular pulse had a significant effect on the inactivation of staphylococcus aureus. Rectangular pulses with a rising time of 200 ns had a better inactivation effect than that with 2 μs. In addition, temperature increase of the solution treated by pulses with 200 ns rising time was lower than that with 2 μs. In order to obtain a given inactivation effect, treatment time required for the rectangular pulse with 200 ns rise time was shorter than that with 2 μs.

  11. Effect of rising time of rectangular pulse on inactivation of staphylococcus aureus by pulsed electric field

    International Nuclear Information System (INIS)

    Zhang, Ruobing; Liang, Dapeng; Xiao, Jianfu; Mo, Mengbin; Li, Jing; Zheng, Nanchen

    2013-01-01

    Pulsed electric field (PEF) is a novel non-thermal food processing technology that involves the electric discharge of high voltage short pulses through the food product. In PEF study, rectangular pulses are most commonly used for inactivating microorganisms. However, little information is available on the inactivation effect of rising time of rectangular pulse. In this paper, inactivation effects, electric field strength, treatment time and conductivity on staphylococcus aureus inactivation were investigated when the pulse rising time is reduced from 2.5 μs to 200 ns. Experimental results showed that inactivation effect of PEF increased with electric field strength, solution conductivity and treatment time. Rising time of the rectangular pulse had a significant effect on the inactivation of staphylococcus aureus. Rectangular pulses with a rising time of 200 ns had a better inactivation effect than that with 2 μs. In addition, temperature increase of the solution treated by pulses with 200 ns rising time was lower than that with 2 μs. In order to obtain a given inactivation effect, treatment time required for the rectangular pulse with 200 ns rise time was shorter than that with 2 μs.

  12. Optical vortex propagation in few-mode rectangular polymer waveguides

    DEFF Research Database (Denmark)

    Lyubopytov, Vladimir S.; Chipouline, Arkadi; Zywietz, Urs

    2017-01-01

    We demonstrate that rectangular few-mode dielectric waveguides, fabricated with standard lithographic technique, can support on-chip propagation of optical vortices. We show that specific superpositions of waveguide eigenmodes form quasi-degenerate modes carrying light with high purity states...

  13. Static and high-frequency magnetic properties of stripe domain structure in a plate of finite sizes

    International Nuclear Information System (INIS)

    Mal'ginova, S.D.; Doroshenko, R.A.; Shul'ga, N.V.

    2006-01-01

    A model that enables to carry out self-consistent calculations of the main parameters of stripe domain structure (DS) and at the same time those of properties of domain walls (DW) of a multiple-axis finite (in all directions) ferromagnet depending on the sizes of a sample, material parameters and intensity of a magnetic field is offered. The calculations of the properties of DS (direction of magnetization in domains, widths, ferromagnetic resonance, etc.) are carried out on a computer for plates (1 1 0), rectangular shapes of a cubic ferromagnet with axes of light magnetization along trigonal directions in a magnetic field [-1 1 0]. It is shown, that in plates of different shapes there can be a structure with Neel DW alongside with DS with Bloch DW. Their features are noticeably exhibited, in particular, in different dependence of the number of domains, and also frequencies of a ferromagnetic resonance from a magnetic field

  14. Use of a vibrating plate to enhance natural convection cooling of a discrete heat source in a vertical channel

    Energy Technology Data Exchange (ETDEWEB)

    Florio, L.A.; Harnoy, A. [Department of Mechanical Engineering, New Jersey Institute of Technology, University Heights, Newark, NJ 07102 (United States)

    2007-09-15

    A numerical investigation was conducted into an alternative method of natural convection enhancement by the transverse oscillations of a thin short plate, strategically positioned in close proximity to a rectangular heat source. The heat source is attached to a mounting board in a vertical channel. Two-dimensional laminar flow finite element studies were carried out with the oscillation parameters, the oscillating plate-heat source mean clearance spacing, and the oscillating plate position varied. Significant cooling was found for displacement amplitudes of at least one-third of the mean clearance together with frequencies (Re/{radical}(Gr)) of over 2{pi} with the displacement being more critical to the cooling level. For the parameters investigated, up to a 52% increase in the local heat transfer coefficient relative to standard natural convection was obtained. The results indicate that this method can serve as a feasible, simpler, more energy and space efficient alternative to common methods of cooling for low power dissipating devices operating at conditions just beyond the reach of pure natural convection. (author)

  15. Optical implementation of (3, 3, 2) regular rectangular CC-Banyan optical network

    Science.gov (United States)

    Yang, Junbo; Su, Xianyu

    2007-07-01

    CC-Banyan network plays an important role in the optical interconnection network. Based on previous reports of (2, 2, 3) the CC-Banyan network, another rectangular-Banyan network, i.e. (3, 3, 2) rectangular CC-Banyan network, has been discussed. First, according to its construction principle, the topological graph and the routing rule of (3, 3, 2) rectangular CC-Banyan network have been proposed. Then, the optically experimental setup of (3, 3, 2) rectangular CC-Banyan network has been designed and achieved. Each stage of node switch consists of phase spatial light modulator (PSLM) and polarizing beam-splitter (PBS), and fiber has been used to perform connection between adjacent stages. PBS features that s-component (perpendicular to the incident plane) of the incident light beam is reflected, and p-component (parallel to the incident plane) passes through it. According to switching logic, under the control of external electrical signals, PSLM functions to control routing paths of the signal beams, i.e. the polarization of each optical signal is rotated or not rotated 90° by a programmable PSLM. Finally, the discussion and analysis show that the experimental setup designed here can realize many functions such as optical signal switch and permutation. It has advantages of large number of input/output-ports, compact in structure, and low energy loss. Hence, the experimental setup can be used in optical communication and optical information processing.

  16. Experimental investigation of effect of flow attack angle on thermohydraulic performance of air flow in a rectangular channel with discrete V-pattern baffle on the heated plate

    Directory of Open Access Journals (Sweden)

    Raj Kumar

    2016-05-01

    Full Text Available In this work, the effect of angle of attack ( α a of the discrete V-pattern baffle on thermohydraulic performance of rectangular channel has been studied experimentally. The baffle wall was constantly heated and the other three walls of the channel were kept insulated. The experimentations were conducted to collect the data on Nusselt number ( N u b and friction factor ( f b by varying the Reynolds number (Re = 3000–21,000 and angle of attack ( α a from 30° to 70°, for the kept values of relative baffle height ( H b / H = 0 . 50 , relative pitch ratio ( P b / H = 1 . 0 , relative discrete width ( g w / H b = 1 . 5 and relative discrete distance ( D d / L v = 0 . 67 . As compared to the smooth wall, the V-pattern baffle roughened channel enhances the Nusselt number ( N u b and friction factor ( f b by 4.2 and 5.9 times, respectively. The present discrete V-pattern baffle shapes with angle of attack ( α a of 60° equivalent to flow Reynolds number of 3000 yields the greatest thermohydraulic performance. Discrete V-pattern baffle has improved thermal performance as compared to other baffle shapes’ rectangular channel.

  17. Analysis of Rectangular Microstrip Antennas with Air Substrates ...

    African Journals Online (AJOL)

    This paper presents an analysis of rectangular microstrip antennas with air substrates. The effect of the substrate thickness on the bandwidth and the efficiency are examined. An additional thin layer supporting the dielectric material is added to the air substrate in order to make the antenna mechanically rigid and easy to ...

  18. FDTD Analysis of U-Slot Rectangular Patch Antenna

    Science.gov (United States)

    Luk, K. M.; Tong, K. F.; Shum, S. M.; Lee, K. F.; Lee, R. Q.

    1997-01-01

    The U-slot rectangular patch antenna (Figure I) has been found experimentally to provide impedance and gain bandwidths of about 300 without the need of stacked or coplanar parasitic elements [1,2]. In this paper, simulation results of the U-slot patch using FDTD analysis are presented. Comparison with measured results are given.

  19. Modal approach for nonlinear vibrations of damped impacted plates: Application to sound synthesis of gongs and cymbals

    Science.gov (United States)

    Ducceschi, M.; Touzé, C.

    2015-05-01

    This paper presents a modal, time-domain scheme for the nonlinear vibrations of perfect and imperfect plates. The scheme can take into account a large number of degrees-of-freedom and is energy-conserving. The targeted application is the sound synthesis of cymbals and gong-like musical instruments, which are known for displaying a strongly nonlinear vibrating behaviour. This behaviour is typical of a wave turbulence regime, in which the wide-band spectrum of excited modes is observable in the form of an energy cascade. The modal method is selected for its versatility in handling complex damping laws that can be implemented easily by selecting appropriate damping values in each one of the modal equations. In the first part of the paper, the modal method is explained in its generality, and it will be seen that the method is valid for plates with arbitrary geometry and boundary conditions as long as the eigenmodes are known. Secondly, a time-integration, energy-conserving scheme for perfect and imperfect plates is presented, and implementation comments are given in order to treat efficiently the high-dimensionality of the resulting dynamical system. The scheme is run with appropriate parameters in order to produce sound samples. A simple impact law is considered for the excitation, whereas the flexibility of the method is highlighted by showing simulations for free-edge circular plates and simply-supported rectangular plates, together with various damping laws.

  20. Internal flow characteristics of a rectangular ramjet air intake

    NARCIS (Netherlands)

    Moerel, J.-L.; Veraar, R.G.; Halswijk, W.H.C.; Pimentel, R.; Corriveau, D.; Hamel, N.; Lesage, F.; Vos, J.B.

    2009-01-01

    Two research institutes TNO Defence, Security and Safety and DRDC-Valcartier have worked together on the improvement of modeling and simulation tools for the functioning of supersonic air intakes for realistic ramjet engines of tactical missiles. The emphasis laid on complex rectangular intake

  1. A Novel Dual-Band Circularly Polarized Rectangular Slot Antenna

    Directory of Open Access Journals (Sweden)

    Biao Li

    2016-01-01

    Full Text Available A coplanar waveguide fed dual-band circularly polarized rectangular slot antenna is presented. The proposed antenna consists of a rectangular metal frame acting as a ground and an S-shaped monopole as a radiator. The spatial distribution of the surface current density is employed to demonstrate that the circular polarization is generated by the S-shaped monopole which controls the path of the surface currents. An antenna prototype, having overall dimension 37 × 37 × 1 mm3, has been fabricated on FR4 substrate with dielectric constant 4.4. The proposed antenna achieves 10 dB return loss bandwidths and 3 dB axial ratio (AR in the frequency bands 2.39–2.81 GHz and 5.42–5.92 GHz, respectively. Both these characteristics are suitable for WLAN and WiMAX applications.

  2. Applicability of electrical resistance tomography to rectangular vessels

    International Nuclear Information System (INIS)

    Ichijo, Noriaki; Matsuno, Shinsuke; Tokura, Susumu; Tochigi, Yoshikatsu; Misumi, Ryuta; Nishi, Kazuhiko; Kaminoyama, Meguru

    2012-01-01

    To ensure a stable operation of Joule-heated glass melters, it is necessary to observe the distribution of platinum group metal particles (noble metals) in molten glass. Electrical resistance tomography (ERT) has a potential to visualize the inside of the melter section because it can be applied at severe conditions such as high temperature and radioactive fields. Due to designing limitations, it is difficult to install electrodes on the wall of the glass melter. In addition, ERT is hardly applied to a rectangular section. To solve these problems, numerical and experimental studies have been implemented. To apply the ERT method, 8 electrodes are inserted from the top of the melter and set near the bottom to visualize the accumulation of noble metals on the bottom area. As a result of the numerical simulation and the experiment, it was clarified that the ERT can be applied to the rectangular vessel by inserting electrodes from the top of the vessel and has a potential to observe the accumulation of noble metals. (author)

  3. Measurement strategy for rectangular electrical capacitance tomography sensor

    International Nuclear Information System (INIS)

    Ye, Jiamin; Ge, Ruihuan; Qiu, Guizhi; Wang, Haigang

    2014-01-01

    To investigate the influence of the measurement strategy for the rectangular electrical capacitance tomography (ECT) sensor, a Finite Element Method (FEM) is utilized to create the model for simulation. The simulation was carried out using COMSOL Multiphysics(trade mark, serif) and Matlab(trade mark, serif). The length-width ratio of the rectangular sensing area is 5. Twelve electrodes are evenly arranged surrounding the pipe. The covering ratio of the electrodes is 90%. The capacitances between different electrode pairs are calculated for a bar distribution. The air of the relative permittivity 1.0 and the material of the permittivity 3.0 are used for the calibration. The relative permittivity of the second phase is 3.0. The noise free and noise data are used for the image reconstruction using the Linear Back Projection (LBP). The measurement strategies with 1-, 2- and 4- electrode excitation are compared using the correlation coefficient. Preliminary results show that the measurement strategy with 2-electrode excitation outperforms other measurement strategies with 1- or 4-electrode excitation

  4. Far-field potentials in cylindrical and rectangular volume conductors.

    Science.gov (United States)

    Dumitru, D; King, J C; Rogers, W E

    1993-07-01

    The occurrence of a transient dipole is one method of producing a far-field potential. This investigation qualitatively defines the characteristics of the near-field and far-field electrical potentials produced by a transient dipole in both cylindrical and rectangular volume conductors. Most body segments of electrophysiologic interest such as arms, legs, thorax, and neck are roughly cylindrical in shape. A centrally located dipole generator produces a nonzero equipotential region which is found to occur along the cylindrical wall at a distance from the dipole of approximately 1.4 times the cylinder's radius and 1.9 times the cylinder's radius for the center of the cylinder. This distance to the equi-potential zone along the surface wall expands but remains less than 3.0 times the cylindrical radius when the dipole is eccentrically placed. The magnitude of the equipotential region resulting from an asymmetrically placed dipole remains identical to that when the dipole is centrally located. This behavior is found to be very similar in rectangular shallow conducting volumes that model a longitudinal slice of the cylinder, thus allowing a simple experimental model of the cylinder to be utilized. Amplitudes of the equipotential region are inversely proportional to the cylindrical or rectangular volume's cross-sectional area at the location of dipolar imbalance. This study predicts that referential electrode montages, when placed at 3.0 times the radius or greater from a dipolar axially aligned far-field generator in cylindrical homogeneous volume conductors, will record only equipotential far-field effects.

  5. Square and Rectangular Arrays from Directed Assembly of Sphere-forming Diblock Copolymers in Thin Films

    Science.gov (United States)

    Ji, Shengxiang; Nagpal, Umang; Liao, Wen; de Pablo, Juan; Nealey, Paul

    2010-03-01

    Patterns of square and rectangular arrays with nanoscale dimensions are scientifically and technologically important. Fabrication of square array patterns in thin films has been demonstrated by directed assembly of cylinder-forming diblock copolymers on chemically patterned substrates, supramolecular assembly of diblock copolymers, and self-assembly of triblock terpolymers. However, a macroscopic area of square array patterns with long-range order has not been achieved, and the fabrication of rectangular arrays has not been reported so far. Here we report a facile approach for fabricating patterns of square and rectangular arrays by directing the assembly of sphere-forming diblock copolymers on chemically patterned substrates. On stripe patterns, a square arrangement of half spheres, corresponding to the (100) plane of the body-centred cubic (BCC) lattice, formed on film surfaces. When the underlying pattern periods mismatched with the copolymer period, the square pattern could be stretched (up to ˜60%) or compressed (˜15%) to form rectangular arrays. Monte Carlo simulations have been further used to verify the experimental results and the 3-dimensional arrangements of spheres.

  6. Motion of rectangular prismatic bodies

    International Nuclear Information System (INIS)

    Poreh, M.; Wray, R.N.

    1979-01-01

    Rectangular prismatic bodies can assume either a translatory or an auto-rotating mode of motion during free motion in the atmosphere. The translatory mode is stable only when the dimensionless moment of inertia of the bodies is large, however, large perturbations will always start auto-rotation. The characteristics of the auto-rotational mode are shown to depend primarily on the aspect ratio of the bodies which determines the dimensionless rotational speed and the lift coefficient. Both the average drag and lift-coefficients of auto-rotating bodies are estimated, but it is shown that secondary effects make it impossible to determine their exact trajectories in atmospheric flows

  7. Effect of cavity inclination on a temperature and concentration controlled double diffusive convection at ice plate melting

    Energy Technology Data Exchange (ETDEWEB)

    Sugawara, M.; Ishikura, T. [Akita University, Department of Mechanical Engineering, Akita (Japan); Beer, H. [Technische Unversitat Darmstadt, Institut fur Technische Thermodynamik, Darmstadt (Germany)

    2005-03-01

    This paper is concerned with the double diffusive convection due to the melting of an ice plate into a calcium chloride aqueous solution inside a rectangular cavity. It is mainly considered the effect of the cavity inclination {theta} on the melting rate and the mean melting Nusselt- and Sherwood-numbers, experimentally as well as numerically. The ice plate melts spontaneously with decreasing temperature at the melting front even if initially there does not exist a temperature difference between the ice and the liquid. The concentration- and temperature-gradients near the melting front induce double diffusive convection in the liquid, which will affect the melting rate. Experiments reveal that the mean melting mass increases monotonically with increasing cavity inclination. The numerical analysis based on the laminar assumption predicts well the melting mass in the range of {theta}=0-90 , however, under-predicts the melting mass in the range of {theta}=90-180 as compared with the experimental results. (orig.)

  8. A modal approach to piano soundboard vibroacoustic behavior

    OpenAIRE

    Trévisan , Benjamin; Ege , Kerem; Laulagnet , Bernard

    2017-01-01

    International audience; This paper presents an analytical method for modeling the vibro-acoustic behavior of ribbed nonrectangular orthotropic clamped plates. To do this, the non-rectangular plate is embedded in an extended rectangular simply supported plate on which a spring distribution is added, blocking theextended part of the surface, and allowing the description of any inner surface shapes. The acoustical radiation of the embedded plate is ensured using the radiation impedances of the e...

  9. 77 FR 5240 - Light-Walled Welded Rectangular Carbon Steel Tubing From Taiwan: Continuation of Antidumping Duty...

    Science.gov (United States)

    2012-02-02

    ... Rectangular Carbon Steel Tubing From Taiwan: Continuation of Antidumping Duty Order AGENCY: Import... revocation of the antidumping duty order on light-walled welded rectangular carbon steel tubing from Taiwan would likely lead to a continuation or recurrence of dumping and material injury to an industry in the...

  10. Release of metal ions from round and rectangular NiTi wires

    Directory of Open Access Journals (Sweden)

    Arash Azizi

    2016-04-01

    Full Text Available Abstract Background The aim of this study was to evaluate the amount of nickel and titanium ions released from two wires with different shapes and a similar surface area. Methods Forty round nickel-titanium (NiTi arch wires with the diameter of 0.020 in. and 40 rectangular NiTi arch wires with the diameter of 0.016 × 0.016 in. were immersed in artificial saliva during a 21-day period. The surface area of both wires was 0.44 in.2. Wires were separately dipped into polypropylene tubes containing 50 ml of buffer solution and were incubated and maintained at 37 °C. Inductively coupled plasma atomic emission spectrometry (ICP-AES was used to measure the amount of ions released after exposure lengths of 1 h, 24 h, 1 week, and 3 weeks. Repeated measures ANOVA and Tukey tests were used to evaluate the data. Results The results indicated that the amount of nickel and titanium concentrations was significantly higher in the rectangular wire group. The most significant release of all metals was measured after the first hour of immersion. In the rectangular wire group, 243 ± 4.2 ng/ml of nickel was released after 1 h, while 221.4 ± 1.7 ng/ml of nickel was released in the round wire group. Similarly, 243.3 ± 2.8 ng/ml of titanium was released in the rectangular wire group and a significantly lower amount of 211.9 ± 2.3 ng/ml of titanium was released in the round wire group. Conclusions Release of metal ions was influenced by the shape of the wire and increase of time.

  11. Modeling particulate removal in plate-plate and wire-plate electrostatic precipitators

    Directory of Open Access Journals (Sweden)

    S Ramechecandane

    2016-09-01

    Full Text Available The present study is concerned with the modeling of electrically charged particles in a model plate-plate and a single wire-plate electrostatic precipitator (ESP. The particle concentration distributions for both a plate-plate and a wire-plate ESP are calculated using a modified drift flux model. Numerical investigations are performed using the modified drift flux model for particle number concentration, in addition to the RNG k - ε model for the mean turbulent flow field and the Poisson equation for the electric field. The proposed model and the outlined methodology for coupling the flow field, electric field, charging kinetics and particle concentration is applied to two model precipitators that are truly representative of a wide class of commercialized ESPs. The present investigation is quite different from the earlier studies as it does not make assumptions like a homogeneous electric field or an infinite turbulent diffusivity. The electric field calculated is a strong function of position and controls the migration velocity of particles. Hence, the proposed model can be implemented in a flow solver to obtain a full-fledged solution for any kind of ESP with no limitations on the particle number concentration, as encountered in a Lagrangian approach. The effect of turbulent diffusivity on particle number concentration in a plate-plate ESP is investigated in detail and the results obtained are compared with available experimental data. Similarly, the effect of particle size/diameter and applied electric potential on the accumulative collection performance in the case of a wire-plate ESP is studied and the results obtained are compared with available numerical data. The numerical results obtained using the modified drift flux model for both the plate-plate and wire-plate ESP are in close agreement with available experimental and numerical data.

  12. Heat transfer and friction characteristics in steam cooled rectangular channels with rib turbulators

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Jianying; Gao, Tieyu; Li, Guojun [Xi' an Jiaotong University, Xi' an (China)

    2014-01-15

    We studied the heat transfer and friction characteristics in steam-cooled rectangular channels with rib turbulators on W side or H side walls in the Reynolds number (Re) range of 10000-80000. Each of the test channels was welded by four stainless steel plates to simulate the actual geometry and heat transfer structure of blade/vane internal cooling passage. The length of the channel L was 1000 mm, the cross section of the channel was 40 mm X 80 mm, and the pitch-to-rib height ratio p/e was kept at 10. The channel blockage ratio (W/H) was 0.047. Results showed that the Nusselt number (Nu) distributions displayed different trends at the entrance region with the increase of Re for the rib turbulators on the W side walls. The heat transfer performance of the rib turbulators on the H side walls was about 24- 27% higher than that on the W side walls at the same pumping power. In addition, semi-empirical correlations for the two cases, rib turbulators on W side walls and rib turbulators on H side walls, were developed based on the heat transfer results, which could be used in the design of the internal cooling passage of new generation steam-cooled gas turbine blade/vane.

  13. Investigation of power battery thermal management by using mini-channel cold plate

    International Nuclear Information System (INIS)

    Huo, Yutao; Rao, Zhonghao; Liu, Xinjian; Zhao, Jiateng

    2015-01-01

    Highlights: • Micro-channel cold plate was used for battery thermal management. • Maximum temperature of battery decreased with the increase of channel number. • Effect of flow direction on cooling performance is smaller with the increase of flow rate. • Cooling performance increased with the increase of inlet flow rate. • The increasing trend become smaller when the flow rate is high enough. - Abstract: In order to guarantee the safety and extend the cycle life of Li-ion power batteries within electric vehicles, a mini-channel cold plate-based battery thermal management system is designed to cool a rectangular Li-ion battery. A three-dimensional thermal model of the cooling system was established and the effects of number of channels, flow direction, inlet mass flow rate and ambient temperature on temperature rise and distribution of the battery during the discharge process were investigated. The results suggest that the maximum temperature of the battery decreases with increases in the number of channels and inlet mass flow rate. The effect of flow direction on cooling performance was smaller after mass flow rate increased. The cooling performance improved with the increase of inlet mass flow rate but the increasing trend became smaller, and the mass flow rate as 5 × 10 −4 kg s −1 was optimal. The simulation results will be useful for the design of mini-channel cold plate-based battery thermal management system

  14. Quantitative analysis of textures produced in a hot-extruded zirconium plate

    International Nuclear Information System (INIS)

    Couterne, J.

    1967-01-01

    The textures produced in zirconium by the extrusion at 730 deg C of a cylindrical billet in the form of a plate having a rectangular cross-section, have been studied by the Schulz method using an isotropic standard. These textures have been determined both parallel to the plane of the plate and parallel to the plane of the sides, All the results are analyzed in a final discussion which makes it possible to show, in particular near the edges of the plate, that certain components of the textures observed in the two series of recordings are in fact aspects of the same texture seen from two different angles, It is shown furthermore that the zirconium thus shaped has cold-work textures and als recrystallisation textures formed after the preceding cold-working, If the observed textures are considered schematically, it can be see that two of these have already been described in the literature and are similar to those found in rolled products: these textures are such that the (0001) planes are inclined at 36 deg C and 60 deg C respectively with respect to a plan tangential to the curve (envelope of transverse flow rates) resulting from the extrusion geometry under consideration; the third texture is defined. by the fact that the (0001) plane is orthogonal to the exterior surfaces of the plate. The direction of extrusion associated with these planes and common to the three textures is of the type , Dilatometric tests have been carried out on samples taken both parallel and perpendicular to the extrusion direction, These tests show that the zirconium is dilatometrically anisotropic and that a plot of (α v )-a against temperature shows a change of gradient at 400 deg C, this latter effect may be due to the change in the electronic configuration of the metal occurring at this temperature. (author) [fr

  15. Critical heat flux of subcooled flow boiling in narrow rectangular channels

    International Nuclear Information System (INIS)

    Kureta, Masatoshi; Akimoto, Hajime

    1999-01-01

    In relation to the high-heat-load devices such as a solid-target cooling channel of a high-intensity neutron source, burnout experiments were performed to obtain critical heat flux (CHF) data systematically for vertical upward flow in one-side heated rectangular channels. One of the objectives of this study was to study an extensibility of existing CHF correlations and models, which were proposed for a round tube, to rectangular channels for design calculation. Existing correlations and models were reviewed and compared with obtained data. Sudo's thin liquid layer dryout model, Griffel correlation and Bernath correlation were in good agreement with the experimental data for short-heated-length and low inlet water temperature conditions. (author)

  16. Turbulent slurry flow measurement using ultrasonic Doppler method in rectangular pipe

    Science.gov (United States)

    Bareš, V.; Krupička, J.; Picek, T.; Brabec, J.; Matoušek, V.

    2014-03-01

    Distribution of velocity and Reynolds stress was measured using ultrasonic velocimetry in flows of water and Newtonian water-ballotini slurries in a pressurized Plexiglas pipe. Profiles of the measured parameters were sensed in the vertical plane at the centreline of a rectangular cross section of the pipe. Reference measurements in clear water produced expected symmetrical velocity profiles the shape of which was affected by secondary currents developed in the rectangular pipe. Slurry-flow experiments provided information on an effect of the concentration of solid grains on the internal structure of the flow. Strong attenuation of velocity fluctuations caused by a presence of grains was identified. The attenuation increased with the increasing local concentration of the grains.

  17. Anisotropic rectangular metric for polygonal surface remeshing

    KAUST Repository

    Pellenard, Bertrand

    2013-06-18

    We propose a new method for anisotropic polygonal surface remeshing. Our algorithm takes as input a surface triangle mesh. An anisotropic rectangular metric, defined at each triangle facet of the input mesh, is derived from both a user-specified normal-based tolerance error and the requirement to favor rectangle-shaped polygons. Our algorithm uses a greedy optimization procedure that adds, deletes and relocates generators so as to match two criteria related to partitioning and conformity.

  18. Anisotropic rectangular metric for polygonal surface remeshing

    KAUST Repository

    Pellenard, Bertrand; Morvan, Jean-Marie; Alliez, Pierre

    2013-01-01

    We propose a new method for anisotropic polygonal surface remeshing. Our algorithm takes as input a surface triangle mesh. An anisotropic rectangular metric, defined at each triangle facet of the input mesh, is derived from both a user-specified normal-based tolerance error and the requirement to favor rectangle-shaped polygons. Our algorithm uses a greedy optimization procedure that adds, deletes and relocates generators so as to match two criteria related to partitioning and conformity.

  19. Hydrodynamics of slug flow in a vertical narrow rectangular channel under laminar flow condition

    International Nuclear Information System (INIS)

    Wang, Yang; Yan, Changqi; Cao, Xiaxin; Sun, Licheng; Yan, Chaoxing; Tian, Qiwei

    2014-01-01

    Highlights: • Slug flow hydrodynamics in a vertical narrow rectangular duct were investigated. • The velocity of trailing Taylor bubble undisturbed by the leading one was measured. • Correlation of Taylor bubble velocity with liquid slug length ahead it was proposed. • Evolution of length distributions of Taylor bubble and liquid slug was measured. • The model of predicted length distributions was applied to the rectangular channel. - Abstract: The hydrodynamics of gas–liquid two-phase slug flow in a vertical narrow rectangular channel with the cross section of 2.2 mm × 43 mm is investigated using a high speed video camera system. Simultaneous measurements of velocity and duration of Taylor bubble and liquid slug made it possible to determine the length distributions of the liquid slug and Taylor bubble. Taylor bubble velocity is dependent on the length of the liquid slug ahead, and an empirical correlation is proposed based on the experimental data. The length distributions of Taylor bubbles and liquid slugs are positively skewed (log-normal distribution) at all measuring positions for all flow conditions. A modified model based on that for circular tubes is adapted to predict the length distributions in the present narrow rectangular channel. In general, the experimental data is well predicted by the modified model

  20. Shielding calculations for changing from circular to a Rectangular ...

    African Journals Online (AJOL)

    The Radiation Technology Centre (RTC) of the Ghana Atomic Energy Commission operates a 1.85 PBq Co-60 gamma irradiator for research, food preservation and medical sterilization. It has become necessary to improve the do-se rate delivered by changing the circular arrangement of sources to a rectangular one.

  1. Numerical analysis and optimization of 3D magnetohydrodynamic flows in rectangular U-bend

    Energy Technology Data Exchange (ETDEWEB)

    He, Qingyun, E-mail: hqingyun@mail.ustc.edu.cn; Feng, Jingchao; Chen, Hongli, E-mail: hlchen1@ustc.edu.cn

    2016-11-01

    Highlights: • MHD flows in rectangular U bends have been investigated under specific magnetic field. • U bends analyzed with different aspect ratio, distance of U bends and the wall conductance ratio. • Pressure optimization of rectangular U bends at corner region. • Studying different inclination of magnetic field cases according to original MHD flows. - Abstract: Liquid metal flow in rectangular bends is a common phenomenon of fusion liquid metal blanket operation, in which the velocity distributions and magnetohydrodynamic (MHD) pressure drop are considered as critical issues. Previous studies mainly aimed at specific fixed geometry for bend flows in LM blanket. The present investigation focuses on numerical analysis of MHD flow in 3D rectangular bends at laminar conditions, which is aimed to reduce MHD pressure drop caused by electromagnetic coupling in conductive flow, especially in bend corner region. The used code has been developed by University of Science and Technology of China (USTC) and validated by recommended benchmark cases such as Shercliff, ALEX experiments and KIT experiment cases, etc. In order to search the optimal duct bending, certain parameters such as different aspect ratio of the duct corner area cross-section, distance of import and export from the elbow and wall conductance ratio have been considered to investigate the pressure drop of MHD flow. Moreover, the effects of different magnetic field direction relative to flow distribution between bends have also been analyzed.

  2. Numerical analysis and optimization of 3D magnetohydrodynamic flows in rectangular U-bend

    International Nuclear Information System (INIS)

    He, Qingyun; Feng, Jingchao; Chen, Hongli

    2016-01-01

    Highlights: • MHD flows in rectangular U bends have been investigated under specific magnetic field. • U bends analyzed with different aspect ratio, distance of U bends and the wall conductance ratio. • Pressure optimization of rectangular U bends at corner region. • Studying different inclination of magnetic field cases according to original MHD flows. - Abstract: Liquid metal flow in rectangular bends is a common phenomenon of fusion liquid metal blanket operation, in which the velocity distributions and magnetohydrodynamic (MHD) pressure drop are considered as critical issues. Previous studies mainly aimed at specific fixed geometry for bend flows in LM blanket. The present investigation focuses on numerical analysis of MHD flow in 3D rectangular bends at laminar conditions, which is aimed to reduce MHD pressure drop caused by electromagnetic coupling in conductive flow, especially in bend corner region. The used code has been developed by University of Science and Technology of China (USTC) and validated by recommended benchmark cases such as Shercliff, ALEX experiments and KIT experiment cases, etc. In order to search the optimal duct bending, certain parameters such as different aspect ratio of the duct corner area cross-section, distance of import and export from the elbow and wall conductance ratio have been considered to investigate the pressure drop of MHD flow. Moreover, the effects of different magnetic field direction relative to flow distribution between bends have also been analyzed.

  3. Bearing capacity of helical pile foundation in peat soil from different, diameter and spacing of helical plates

    Science.gov (United States)

    Fatnanta, F.; Satibi, S.; Muhardi

    2018-03-01

    In an area dominated by thick peat soil layers, driven piles foundation is often used. These piles are generally skin friction piles where the pile tips do not reach hard stratum. Since the bearing capacity of the piles rely on the resistance of their smooth skin, the bearing capacity of the piles are generally low. One way to increase the bearing capacity of the piles is by installing helical plates around the pile tips. Many research has been performed on helical pile foundation. However, literature on the use of helical pile foundation on peat soil is still hardly found. This research focus on the study of axial bearing capacity of helical pile foundation in peat soil, especially in Riau Province. These full-scale tests on helical pile foundation were performed in a rectangular box partially embedded into the ground. The box is filled with peat soil, which was taken from Rimbo Panjang area in the district of Kampar, Riau Province. Several helical piles with different number, diameter and spacing of the helical plates have been tested and analysed. The tests result show that helical pile with three helical plates of uniform diameter has better bearing capacity compared to other helical piles with varying diameter and different number of helical plates. The bearing capacity of helical pile foundation is affected by the spacing between helical plates. It is found that the effective helical plates spacing for helical pile foundation with diameter of 15cm to 35cm is between 20cm to 30cm. This behaviour may be considered to apply to other type of helical pile foundations in peat soil.

  4. Rarefied gas flow in a rectangular enclosure induced by non-isothermal walls

    Energy Technology Data Exchange (ETDEWEB)

    Vargas, Manuel; Tatsios, Giorgos; Valougeorgis, Dimitris, E-mail: diva@mie.uth.gr [Department of Mechanical Engineering, University of Thessaly, 38334 Volos (Greece); Stefanov, Stefan [Institute of Mechanics, Bulgarian Academy of Sciences, Sofia (Bulgaria)

    2014-05-15

    The flow of a rarefied gas in a rectangular enclosure due to the non-isothermal walls with no synergetic contributions from external force fields is investigated. The top and bottom walls are maintained at constant but different temperatures and along the lateral walls a linear temperature profile is assumed. Modeling is based on the direct numerical solution of the Shakhov kinetic equation and the Direct Simulation Monte Carlo (DSMC) method. Solving the problem both deterministically and stochastically allows a systematic comparison and verification of the results as well as the exploitation of the numerical advantages of each approach in the investigation of the involved flow and heat transfer phenomena. The thermally induced flow is simulated in terms of three dimensionless parameters characterizing the problem, namely, the reference Knudsen number, the temperature ratio of the bottom over the top plates, and the enclosure aspect ratio. Their effect on the flow configuration and bulk quantities is thoroughly examined. Along the side walls, the gas flows at small Knudsen numbers from cold-to-hot, while as the Knudsen number is increased the gas flows from hot-to-cold and the thermally induced flow configuration becomes more complex. These flow patterns with the hot-to-cold flow to be extended to the whole length of the non-isothermal side walls may exist even at small temperature differences and then, they are enhanced as the temperature difference between the top and bottom plates is increased. The cavity aspect ratio also influences this flow configuration and the hot-to-cold flow is becoming more dominant as the depth compared to the width of the cavity is increased. To further analyze the flow patterns a novel solution decomposition into ballistic and collision parts is introduced. This is achieved by accordingly modifying the indexing process of the typical DSMC algorithm. The contribution of each part of the solution is separately examined and a physical

  5. Plasma-filled rippled wall rectangular backward wave oscillator

    Indian Academy of Sciences (India)

    Performance of the backward wave oscillator (BWO) is greatly enhanced with the introduction of plasma. Linear theory of the dispersion relation and the growth rate have been derived and analysed numerically for plasma-filled rippled wall rectangular waveguide driven by sheet electron beam. To see the effect of plasma ...

  6. The analysis of radiation parameters dependence of rectangular waveguide on its dimensions change

    Directory of Open Access Journals (Sweden)

    Manoilov V.P.

    2016-04-01

    Full Text Available Analysis of radiation from 3 centimeter waveband rectangular waveguide at the change of the side sizes is carried out for the purpose of efficiency estimation of its use as reflector parabolic antenna exciter. Some performance characteristics of radioelectronic systems depend on antennas types which are used. Recently, the development of antenna systems occurred mainly not by creating new, and by improving the parameters and characteristics of existing antennas. Therefore, there is a practical need to find ways to improve their elements. A detailed analysis of the radiation from the open end of the rectangular waveguide allows to specify exactly which of its parameters and characteristics need to be improved. Dependence charts of directional diagram (DD in planes E and H, radiation power, directivity upon variation of side sizes a, b are received. Dependence charts of attenuation coefficient upon frequency for wave types H10, H01, H02, H11, E11 are drawn up. Estimation of reasonability of using rectangular waveguide as reflector parabolic antenna exciter is received.

  7. Design and construction of a mode converter from TE10(rectangular) to TE11(circular)

    International Nuclear Information System (INIS)

    Tubbing, B.J.D.

    1984-08-01

    The design and manufacturing of a wavelength mode converter from the TE 10 (rectangular) mode in oversized rectangular to the TE 11 (circular) mode in oversized circular waveguide is described. A differential equation for the cross-sectional shape of the converter was solved numerically. A stainless-steel mandrel was produced on a numerically controlled milling machine. Sixteen converters were produced by means of electroforming on one mandrel. (Auth.)

  8. 76 FR 64312 - Light-Walled Welded Rectangular Carbon Steel Tubing From Taiwan: Final Results of the Expedited...

    Science.gov (United States)

    2011-10-18

    ... Rectangular Carbon Steel Tubing From Taiwan: Final Results of the Expedited Sunset Review of the Antidumping... the antidumping duty order on light-walled welded rectangular carbon steel tubing from Taiwan pursuant... steel tubing from Taiwan pursuant to section 751(c) of the Act. See Initiation of Five-Year (``Sunset...

  9. Hydrodynamics of a flexible plate between pitching rigid plates

    Science.gov (United States)

    Kim, Junyoung; Kim, Daegyoum

    2017-11-01

    The dynamics of a flexible plate have been studied as a model problem in swimming and flying of animals and fluid-structure interaction of plants and flags. Motivated by fish schooling and an array of sea grasses, we investigate the dynamics of a flexible plate closely placed between two pitching rigid plates. In most studies on passive deformation of the flexible plate, the plate is immersed in a uniform flow or a wavy flow. However, in this study, the flexible plate experiences periodic deformation by the oscillatory flow generated by the prescribed pitching motion of the rigid plates. In our model, the pitching axes of the rigid plates and the clamping position of the flexible plate are aligned on the same line. The flexible plate shows various responses depending on length and pitching frequency of rigid plates, thickness of a flexible plate, and free-stream velocity. To find the effect of each variable on the response of the flexible plate, amplitude of a trailing edge and modal contribution of a flapping motion are compared, and flow structure around the flexible plate is examined.

  10. Experimental investigation on flow instability of forced circulation in a vertical mini-rectangular channel

    International Nuclear Information System (INIS)

    Yu Zhiting; Tan Sichao; Yuan Hongsheng; Zhuang Nailiang; Chen Hanying

    2015-01-01

    An experimental study was conducted to investigate the flow instability in a vertical mini-rectangular channel with distilled water as the working fluid. The rotational speed of the primary pump is gradually reduced to lower the inlet flow rate until the flow becomes unstable, while maintaining all other thermal parameters unchanged. Three types of instability, characterized by large amplitude oscillation, small amplitude oscillation and flow excursion, were identified from the experimental data. A stability map for the vertical mini-rectangular channel under forced circulation was established based on the Subcooling number and Phase Change number. The oscillation periods were correlated with the fluid transit time and the boiling delay time. A flow pattern map for vertical upward flow in a mini-rectangular channel was applied to confirm the flow patterns during the oscillation. The mechanisms of the three types of instability were obtained by considering several types of flow instabilities and comparing them with the oscillations observed in this work. (author)

  11. Forced convective boiling heat transfer of water in vertical rectangular narrow channel

    International Nuclear Information System (INIS)

    Chen, Chong; Gao, Pu-zhen; Tan, Si-chao; Chen, Han-ying; Chen, Xian-bing

    2015-01-01

    Highlights: • Chen correlation cannot well predict the coefficient of rectangular channel. • Kim and Mudawar correlation is the best one among the Chen type correlations. • Lazarek and Black correlation predicted 7.0% of data within the ±30% error band. • The new correlation can well predict the coefficient with a small MAE of 14.4%. - Abstract: In order to research the characteristics of boiling flows in a vertical rectangular narrow channel, a series of convective boiling heat transfer experiments are performed. The test section is made of stainless steel with an inner diameter of 2 × 40 mm and heated length of 1100 mm. The 3194 experimental data points are obtained for a heat flux range of 10–700 kW/m 2 , a mass flux range of 200–2400 kg/m 2 s, a system pressure range of 0.1–2.5 MPa, and a quality range of 0–0.8. Eighteen prediction models are used to predict the flow boiling heat transfer coefficient of the rectangular narrow channel and the predicted value is compared against the database including 3194 data points, the results show that Chen type correlations and Lazarek and Black type correlations are not suitable for the rectangular channel very much. The Kim and Mudawar correlation is the best one among the 18 models. A new correlation is developed based on the superposition concept of nucleate boiling and convective boiling. the new correlation is shown to provide a good prediction against the database, evidenced by an overall MAE of 14.4%, with 95.2% and 98.6% of the data falling within ±30% and ±35% error bands, respectively

  12. Comparison of air-standard rectangular cycles with different specific heat models

    International Nuclear Information System (INIS)

    Wang, Chao; Chen, Lingen; Ge, Yanlin; Sun, Fengrui

    2016-01-01

    Highlights: • Air-standard rectangular cycle models are built and investigated. • Finite-time thermodynamics is applied. • Different dissipation models and variable specific heats models are adopted. • Performance characteristics of different cycle models are compared. - Abstract: In this paper, performance comparison of air-standard rectangular cycles with constant specific heat (SH), linear variable SH and non-linear variable SH are conducted by using finite time thermodynamics. The power output and efficiency of each cycle model and the characteristic curves of power output versus compression ratio, efficiency versus compression ratio, as well as power output versus efficiency are obtained by taking heat transfer loss (HTL) and friction loss (FL) into account. The influences of HTL, FL and SH on cycle performance are analyzed by detailed numerical examples.

  13. Rectangular-to-quincunx Gabor lattice conversion via fractional Fourier transformation

    NARCIS (Netherlands)

    Bastiaans, M.J.; Leest, van A.J.

    1998-01-01

    Transformations of Gabor lattices are associated with operations on the window functions that arise in Gabor theory. In particular it is shown that transformation from a rectangular to a quincunx lattice can be associated with fractional Fourier transformation. Since a Gaussian function, which plays

  14. Positronium behaviour in elongated PPT, rectangular MgO and spherical Si nanocavities

    International Nuclear Information System (INIS)

    Eijt, S.W.H.; Falub, C.V.; Mijnarends, P.E.; Veen, A. van

    2001-01-01

    The 2D-ACAR para-Ps (p-Ps) spectrum of PPT aramid fibres, which contain structural elongated open spaces in the unit cell, is compared with the spectrum calculated for a Ps wave function in a rectangular cavity. Helium ion implantation in MgO and Si single crystals creates thin layers of nanosize rectangular and spherical cavities, respectively. Depth-selective 2D-ACAR experiments at the positron centre Delft allow the extraction of the p-Ps contribution from the spectra. In both samples p-Ps is not thermalised and has an average energy of the order of a few eV. The energy and momentum distribution of the Ps atoms are extracted and compared with Maxwell distributions. (orig.)

  15. Positronium behaviour in elongated PPT, rectangular MgO and spherical Si nanocavities

    Energy Technology Data Exchange (ETDEWEB)

    Eijt, S.W.H.; Falub, C.V.; Mijnarends, P.E.; Veen, A. van [Interfaculty Reactor Inst., Delft Univ. of Technology (Netherlands)

    2001-07-01

    The 2D-ACAR para-Ps (p-Ps) spectrum of PPT aramid fibres, which contain structural elongated open spaces in the unit cell, is compared with the spectrum calculated for a Ps wave function in a rectangular cavity. Helium ion implantation in MgO and Si single crystals creates thin layers of nanosize rectangular and spherical cavities, respectively. Depth-selective 2D-ACAR experiments at the positron centre Delft allow the extraction of the p-Ps contribution from the spectra. In both samples p-Ps is not thermalised and has an average energy of the order of a few eV. The energy and momentum distribution of the Ps atoms are extracted and compared with Maxwell distributions. (orig.)

  16. Sadhana | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Buckling analysis of rectangular composite plates with rectangular cutout subjected to ... Design of RC frames for pre-selected collapse mechanism and target ... of an old building's column retrofitted with steel plate in an in situ pushover test ... plastic hinge occurs at about 2% storey drift ratio, and that the DIC technique can ...

  17. Droplet size in a rectangular Venturi scrubber

    OpenAIRE

    Costa, M. A. M.; Henrique, P. R.; Gonçalves, J. A. S.; Coury, J.R.

    2004-01-01

    The Venturi scrubber is a device which uses liquid in the form of droplets to efficiently remove fine particulate matter from gaseous streams. Droplet size is of fundamental importance for the scrubber performance. In the present experimental study, a laser diffraction technique was used in order to measure droplet size in situ in a Venturi scrubber with a rectangular cross section. Droplet size distribution was measured as a function of gas velocity (58.3 to 74.9 m/s), liquid-to-gas ratio (0...

  18. Conformal boundary state for the rectangular geometry

    Energy Technology Data Exchange (ETDEWEB)

    Bondesan, R., E-mail: roberto.bondesan@cea.fr [Institute de Physique Theorique, CEA Saclay, F-91191 Gif-sur-Yvette (France); LPTENS, Ecole Normale Superieure, 24 rue Lhomond, 75231 Paris (France); Institut Henri Poincare, 11 rue Pierre et Marie Curie, 75231 Paris (France); Dubail, J. [Department of Physics, Yale University, P.O. Box 208120, New Haven, CT 06520-8120 (United States); Jacobsen, J.L. [LPTENS, Ecole Normale Superieure, 24 rue Lhomond, 75231 Paris (France); Institut Henri Poincare, 11 rue Pierre et Marie Curie, 75231 Paris (France); Universite Pierre et Marie Curie, 4 place Jussieu, 75252 Paris (France); Saleur, H. [Institute de Physique Theorique, CEA Saclay, F-91191 Gif-sur-Yvette (France); Institut Henri Poincare, 11 rue Pierre et Marie Curie, 75231 Paris (France); Physics Department, USC, Los Angeles, CA 90089-0484 (United States)

    2012-09-11

    We discuss conformal field theories (CFTs) in rectangular geometries, and develop a formalism that involves a conformal boundary state for the 1+1d open system. We focus on the case of homogeneous boundary conditions (no insertion of a boundary condition changing operator), for which we derive an explicit expression of the associated boundary state, valid for any arbitrary CFT. We check the validity of our solution, comparing it with known results for partition functions, numerical simulations of lattice discretizations, and coherent state expressions for free theories.

  19. Unified model for the electromechanical coupling factor of orthorhombic piezoelectric rectangular bar with arbitrary aspect ratio

    Directory of Open Access Journals (Sweden)

    R. Rouffaud

    2017-02-01

    Full Text Available Piezoelectric Single Crystals (PSC are increasingly used in the manufacture of ultrasonic transducers and in particular for linear arrays or single element transducers. Among these PSCs, according to their microstructure and poled direction, some exhibit a mm2 symmetry. The analytical expression of the electromechanical coupling coefficient for a vibration mode along the poling direction for piezoelectric rectangular bar resonator is established. It is based on the mode coupling theory and fundamental energy ratio definition of electromechanical coupling coefficients. This unified formula for mm2 symmetry class material is obtained as a function of an aspect ratio (G where the two extreme cases correspond to a thin plate (with a vibration mode characterized by the thickness coupling factor, kt and a thin bar (characterized by k33′. To optimize the k33′ value related to the thin bar design, a rotation of the crystallogaphic axis in the plane orthogonal to the poling direction is done to choose the highest value for PIN-PMN-PT single crystal. Finally, finite element calculations are performed to deduce resonance frequencies and coupling coefficients in a large range of G value to confirm developed analytical relations.

  20. Electroosmotic flow in a rectangular channel with variable wall zeta-potential: comparison of numerical simulation with asymptotic theory.

    Science.gov (United States)

    Datta, Subhra; Ghosal, Sandip; Patankar, Neelesh A

    2006-02-01

    Electroosmotic flow in a straight micro-channel of rectangular cross-section is computed numerically for several situations where the wall zeta-potential is not constant but has a specified spatial variation. The results of the computation are compared with an earlier published asymptotic theory based on the lubrication approximation: the assumption that any axial variations take place on a long length scale compared to a characteristic channel width. The computational results are found to be in excellent agreement with the theory even when the scale of axial variations is comparable to the channel width. In the opposite limit when the wavelength of fluctuations is much shorter than the channel width, the lubrication theory fails to describe the solution either qualitatively or quantitatively. In this short wave limit the solution is well described by Ajdari's theory for electroosmotic flow between infinite parallel plates (Ajdari, A., Phys. Rev. E 1996, 53, 4996-5005.) The infinitely thin electric double layer limit is assumed in the theory as well as in the simulation.

  1. On the prestressing and deformation of rectangular particle detector frames

    International Nuclear Information System (INIS)

    Margulies, S.

    1978-01-01

    Particle detectors such as spark chambers and multiwire proportional chambers (MWPC) generally contain planar electrodes stretched across rectangular frames. For detectors of reasonable size, this can result in fairly large forces acting on the frames. To maintain the electrode planes under uniform tension and to prevent sagging, the frames must be prestressed. This paper contains a detailed examination of the deformation of rectangular frames under stress. A simple model for this phenomenon is presented. The model consists of treating each side of the frame as an elastic beam subject to the condition that the sides remain perpendicular at the corners. The predictions of the model are in good agreement with measured deflections of a MWPC frame. The model is used to determine the optimum value of a single concentrated prestressing force F to best approximate the total distributed force W of a uniformly tensed electrode plane. For most geometries it is found that F is about 62% of W. (Auth.)

  2. A Rectangular Planar Spiral Antenna for GIS Partial Discharge Detection

    Directory of Open Access Journals (Sweden)

    Xiaoxing Zhang

    2014-01-01

    Full Text Available A rectangular planar spiral antenna sensor was designed for detecting the partial discharge in gas insulation substations (GIS. It can expediently receive electromagnetic waves leaked from basin-type insulators and can effectively suppress low frequency electromagnetic interference from the surrounding environment. Certain effective techniques such as rectangular spiral structure, bow-tie loading, and back cavity structure optimization during the antenna design process can miniaturize antenna size and optimize voltage standing wave ratio (VSWR characteristics. Model calculation and experimental data measured in the laboratory show that the antenna possesses a good radiating performance and a multiband property when working in the ultrahigh frequency (UHF band. A comparative study between characteristics of the designed antenna and the existing quasi-TEM horn antenna was made. Based on the GIS defect simulation equipment in the laboratory, partial discharge signals were detected by the designed antenna, the available quasi-TEM horn antenna, and the microstrip patch antenna, and the measurement results were compared.

  3. The calculation of dose rates from rectangular sources

    International Nuclear Information System (INIS)

    Hartley, B.M.

    1998-01-01

    A common problem in radiation protection is the calculation of dose rates from extended sources and irregular shapes. Dose rates are proportional to the solid angle subtended by the source at the point of measurement. Simple methods of calculating solid angles would assist in estimating dose rates from large area sources and therefore improve predictive dose estimates when planning work near such sources. The estimation of dose rates is of particular interest to producers of radioactive ores but other users of bulk radioactive materials may have similar interest. The use of spherical trigonometry can assist in determination of solid angles and a simple equation is derived here for the determination of the dose at any distance from a rectangular surface. The solid angle subtended by complex shapes can be determined by modelling the area as a patchwork of rectangular areas and summing the solid angles from each rectangle. The dose rates from bags of thorium bearing ores is of particular interest in Western Australia and measured dose rates from bags and containers of monazite are compared with theoretical estimates based on calculations of solid angle. The agreement is fair but more detailed measurements would be needed to confirm the agreement with theory. (author)

  4. Mechanical behavior analysis on electrostatically actuated rectangular microplates

    Science.gov (United States)

    Li, Zhikang; Zhao, Libo; Jiang, Zhuangde; Ye, Zhiying; Dai, Lu; Zhao, Yulong

    2015-03-01

    Microplates are widely used in various MEMS devices based on electrostatic actuation such as MEMS switches, micro pumps and capacitive micromachined ultrasonic transducers (CMUTs). Accurate predictions for the mechanical behavior of the microplate under electrostatic force are important not only for the design and optimization of these electrostatic devices but also for their operation. This paper presents a novel reduced-order model for electrostatically actuated rectangular and square microplates with a new method to treat the nonlinear electrostatic force. The model was developed using Galerkin method which turned the partial-differential equation governing the microplates into an ordinary equation system. Using this model and cosine-like deflection functions, explicit expressions were established for the deflection and pull-in voltage of the rectangular and square microplates. The theoretical results were well validated with the finite element method simulations and experimental data of literature. The expressions for the deflection analysis are able to predict the deflection up to the pull-in position with an error less than 5.0%. The expressions for the pull-in voltage analysis can determine the pull-in voltages with errors less than 1.0%. Additionally, the method to calculate the capacitance variation of the electrostatically actuated microplates was proposed. These theoretical analyses are helpful for design and optimization of electrostatically actuated microdevices.

  5. On the evaluation of rectangular plane-extended sources and their associated radiation fields

    International Nuclear Information System (INIS)

    Oner, Feda

    2007-01-01

    The objective of this paper is to provide an efficient and reliable analytical procedure for the evaluation of rectangular plane-extended sources and their associated radiation fields. Integrals with integer and non-integer values appear in the evaluation of the radiation field distribution. The latter results from a homogeneous rectangular plane target bombarded by hollow-cylindrical ion beams, the elementary areas anisotropically emitting in non-dispersive media, and fast neutrons produced in non-dispersive media by sealed-off neutron generating tubes (NGT) in an axi-symmetric situation [Hubbell, J.H., Bach, R.L., Lamkin, J.C., 1960. Radiation from a rectangular source. J. Res. NBS 64C (2), 121-137; Hubbell, J.H., 1963a. A power series buildup factor formulation. Application to rectangular and offaxis disk source problems. J. Res. NBS 67C, 291-306, Hubbell, J.H., 1963b. Dose fields from plane sources using point-source data. Nucleonics 21 (8), 144-148; Timus et al., 2005a. Plane rectengular tritium target response to excitation by uniform distributed normal accelerated deuteron beam. Appl. Radiat. Isot. 63, 823-839; Timus et al., 2005b. Analytical characterization of radiation fields generated by certain witch-type distributed axi-symmetrical ion beams. Arab J. Nucl. Sci. Appl. 38(I) 253-264]. In these references, the resulting expressions are represented as infinite linear combinations of basic J q (a, b, z) integrals. With the help of relation for J q (a, b, z), we can evaluate the high terms of energy expressions, which have been proposed in the above-mentioned references. The extensive test calculations show that the proposed algorithm in this work is the most efficient one in practical computations

  6. Development of a design methodology for hydraulic pipelines carrying rectangular capsules

    International Nuclear Information System (INIS)

    Asim, Taimoor; Mishra, Rakesh; Abushaala, Sufyan; Jain, Anuj

    2016-01-01

    The scarcity of fossil fuels is affecting the efficiency of established modes of cargo transport within the transportation industry. Efforts have been made to develop innovative modes of transport that can be adopted for economic and environmental friendly operating systems. Solid material, for instance, can be packed in rectangular containers (commonly known as capsules), which can then be transported in different concentrations very effectively using the fluid energy in pipelines. For economical and efficient design of such systems, both the local flow characteristics and the global performance parameters need to be carefully investigated. Published literature is severely limited in establishing the effects of local flow features on system characteristics of Hydraulic Capsule Pipelines (HCPs). The present study focuses on using a well validated Computational Fluid Dynamics (CFD) tool to numerically simulate the solid-liquid mixture flow in both on-shore and off-shore HCPs applications including bends. Discrete Phase Modelling (DPM) has been employed to calculate the velocity of the rectangular capsules. Numerical predictions have been used to develop novel semi-empirical prediction models for pressure drop in HCPs, which have then been embedded into a robust and user-friendly pipeline optimisation methodology based on Least-Cost Principle. - Highlights: • Local flow characteristics in a pipeline transporting rectangular capsules. • Development of prediction models for the pressure drop contribution of capsules. • Methodology developed for sizing of Hydraulic Capsule Pipelines. • Implementation of the developed methodology to obtain optimal pipeline diameter.

  7. Two-phase flow patterns in horizontal rectangular minichannel

    Directory of Open Access Journals (Sweden)

    Ron’shin Fedor

    2016-01-01

    Full Text Available The two-phase flow in a short horizontal channel of rectangular cross-section of 1 × 19 mm2 has been studied experimentally. Five conventional two-phase flow patterns have been detected (bubble, churn, stratified, annular and jet and transitions between them have been determined. It is shown that a change in the width of the horizontal channels has a substantial effect on the boundaries between the flow regimes.

  8. Plasmonic band-stop filter with asymmetric rectangular ring for WDM networks

    International Nuclear Information System (INIS)

    Nezhad, Vahid Foroughi; Abrishamian, Mohammad Sadegh; Abaslou, Siamak

    2013-01-01

    We proposed a simple asymmetric rectangular band-stop filter based on metal–insulator–metal plasmonic waveguides. It is shown that the performance of the structure as a filter strongly depends on the asymmetry of the rectangular structure. An analytical model based on the analogy between MDM waveguides and the microwave transmission line is used to calculate the resonance wavelengths and explain the behavior of the filter. The bandwidth of spectra can be easily manipulated by adjusting the topological parameters of the filter. It is also demonstrated that by adjusting the bandwidth, the filter can be used for CWDM standard channels. The filter behavior is verified using the numerical finite difference time domain (FDTD) method. The filter is compact and has a footprint of 1 μm × 0.5 μm, which is suitable for integrated optical circuits. (paper)

  9. Effects of the Strain Rate Sensitivity and Strain Hardening on the Saturated Impulse of Plates

    Directory of Open Access Journals (Sweden)

    Ling Zhu

    Full Text Available Abstract This paper studies the stiffening effects of the material strain rate sensitivity and strain hardening on the saturated impulse of elastic, perfectly plastic plates. Finite element (FE code ABAQUS is employed to simulate the elastoplastic response of square plates under rectangular pressure pulse. Rigid-plastic analyses for saturated impulse, which consider strain rate sensitivity and strain hardening, are conducted. Satisfactory agreement between the finite element models (FEM and predictions of the rigid-plastic analysis is obtained, which verifies that the proposed rigid-plastic methods are effective to solve the problem including strain rate sensitivity and strain hardening. The quantitative results for the scale effect of the strain rate sensitivity are given. The results for the stiffening effects suggest that two general stiffening factors n 1 and n 2, which characterizes the strain rate sensitivity and strain hardening effect, respectively can be defined. The saturated displacement is inversely proportional to the stiffening factors (i.e. n 1 and n 2 and saturated impulse is inversely proportional to the square roots of the stiffening factors (i.e. n 1 and n 2. Formulae for displacement and saturated impulse are proposed based on the empirical analysis.

  10. Flows around a moving flat plate simulated by the method of cellular automata. Seru outoman ho ni yoru ido heiban mawari no nagare

    Energy Technology Data Exchange (ETDEWEB)

    Tsutahara, M; Tomiyama, A; Kimura, T; Murata, H [Kobe University, Kobe (Japan). Faculty of Engineering

    1993-08-25

    In order to analyze the field of flow containing a moving boundary by the method of cellular automaton, the method of giving the boundary conditions in the case where a wall is moving at a constant velocity in the normal direction was examined. This method is used to simulate the movement of continuous fluid by statistically treating the movement of many discrete particles which repeat translation and collision. The collision law of particles at grid points is formulated so as to conserve mass(number of particles) and momentum for the purpose of satisfying the governing equation of flow. The object is the flow in the case where a flat plate moves in the normal direction inside the fluid enclosed by rectangular walls and the plate was assumed that it is first in a standing condition, then starts to move from left to right at a speed of V and stops in front of the right wall. Three boundary conditions, surrounding wall, plate in the standing condition and moving plate, were considered. Flow rates were calculated concerning the translation and collision and each divided mean-field-approximation region(space having a magnitude of capable of averaging operation of particles). Effectiveness of proposed boundary conditions was confirmed by a visualization experiment. 3 refs., 14 figs.

  11. High-voltage nanosecond Marx generator with quasi-rectangular pulses

    International Nuclear Information System (INIS)

    Bulan, V.V.; Grabovskij, E.V.; Gribov, A.N.; Luzhnov, V.G.

    1999-01-01

    The automated high-voltage nanosecond generator, forming single pulses of any polarity on the load of 17 Ohm with polarity voltage from 100 up to 300 kV at the semiheight of 80 ns and the front of 7 ns is described. The generator is assembled on the basis of low-inductive capacitors, which by discharge form the pulse, close by form to rectangular one [ru

  12. Traffic of leukocytes in microfluidic channels with rectangular and rounded cross-sections.

    Science.gov (United States)

    Yang, Xiaoxi; Forouzan, Omid; Burns, Jennie M; Shevkoplyas, Sergey S

    2011-10-07

    Traffic of leukocytes in microvascular networks (particularly through arteriolar bifurcations and venular convergences) affects the dynamics of capillary blood flow, initiation of leukocyte adhesion during inflammation, and localization and development of atherosclerotic plaques in vivo. Recently, a growing research effort has been focused on fabricating microvascular networks comprising artificial vessels with more realistic, rounded cross-sections. This paper investigated the impact of the cross-sectional geometry of microchannels on the traffic of leukocytes flowing with human whole blood through a non-symmetrical bifurcation that consisted of a 50 μm mother channel bifurcating into 30 μm and 50 μm daughter branches. Two versions of the same bifurcation comprising microchannels with rectangular and rounded cross-sections were fabricated using conventional multi-layer photolithography to produce rectangular microchannles that were then rounded in situ using a recently developed method of liquid PDMS/air bubble injection. For microchannels with rounded cross-sections, about two-thirds of marginated leukocytes traveling along a path in the top plane of the bifurcation entered the smallest 30 μm daughter branch. This distribution was reversed in microchannels with rectangular cross-sections--the majority of leukocytes traveling along a similar path continued to follow the 50 μm microchannels after the bifurcation. This dramatic difference in the distribution of leukocyte traffic among the branches of the bifurcation can be explained by preferential margination of leukocytes towards the corners of the 50 μm mother microchannels with rectangular cross-sections, and by the additional hindrance to leukocyte entry created by the sharp transition from the 50 μm mother microchannel to the 30 μm daughter branch at the intersection. The results of this study suggest that the trajectories of marginated leukocytes passing through non-symmetrical bifurcations are

  13. Biomechanical evaluation of immediate stability with rectangular versus cylindrical interbody cages in stabilization of the lumbar spine

    Directory of Open Access Journals (Sweden)

    Webb John K

    2002-10-01

    Full Text Available Abstract Background Recent cadaver studies show stability against axial rotation with a cylindrical cage is marginally superior to a rectangular cage. The purpose of this biomechanical study in cadaver spine was to evaluate the stability of a new rectangular titanium cage design, which has teeth similar to the threads of cylindrical cages to engage the endplates. Methods Ten motion segments (five L2-3, five L4-5 were tested. From each cadaver spine, one motion segment was fixed with a pair of cylindrical cages (BAK, Sulzer Medica and the other with paired rectangular cages (Rotafix, Corin Spinal. Each specimen was tested in an unconstrained state, after cage introduction and after additional posterior translaminar screw fixation. The range of motion (ROM in flexion-extension, lateral bending, and rotation was tested in a materials testing machine, with +/- 5 Nm cyclical load over 10 sec per cycle; data from the third cycle was captured for analysis. Results ROM in all directions was significantly reduced (p Conclusions There was no significant difference in immediate stability in any direction between the threaded cylindrical cage and the new design of the rectangular cage with endplate teeth.

  14. Rectangular source integral and recurrence relations

    International Nuclear Information System (INIS)

    Prabha, Hem

    2007-01-01

    In this paper Hubbell's rectangular source integral H'(a,b), which is a double integral, is expressed as a series of many converging single integrals I n (a,b). Recurrence relations relate these integrals. Once one integral I 1 is computed, recurrence relations are used to compute other integrals. I 1 (a,b) can be computed analytically. H'(a,b) is approximated by considering the first seven terms in the series and the results are found to give good results for various values of a and b. Results are presented for the values of a and b (0.1 to 20 and to 2), respectively. The rate of convergence depends on the values of a and b

  15. Three-dimensional detonation cellular structures in rectangular ducts using an improved CESE scheme

    KAUST Repository

    Shen, Yang

    2016-11-01

    The three-dimensional premixed H2-O2 detonation propagation in rectangular ducts is simulated using an in-house parallel detonation code based on the second-order space–time conservation element and solution element (CE/SE) scheme. The simulation reproduces three typical cellular structures by setting appropriate cross-sectional size and initial perturbation in square tubes. As the cross-sectional size decreases, critical cellular structures transforming the rectangular or diagonal mode into the spinning mode are obtained and discussed in the perspective of phase variation as well as decreasing of triple point lines. Furthermore, multiple cellular structures are observed through examples with typical aspect ratios. Utilizing the visualization of detailed three-dimensional structures, their formation mechanism is further analyzed.

  16. Study on critical heat flux based on wavelet transform in rectangular narrow channels

    International Nuclear Information System (INIS)

    Zhou Tao; Ju Zhongyun; Zhang Lei; Li Jingjing; Sheng Cheng; Xiao Zejun

    2014-01-01

    Critical heat flux is very important for nuclear reactor safety, and observing temperature rise rate is a feasible method. Through using the wavelet transform to analyze the CHF temperature rise curves in rectangular narrow channels, it can remove relative weaker interference and effectively judge CHF. Rectangular narrow channel can strengthen heat transfer and reduce CHF, whose characteristics are proved by, temperature rise curves analyzed by wavelet transform. Respectively applying Daubechies function and Haar function is for guarantee the accuracy of the wavelet analysis, and Daubechies function is more accurate than Haar function in the detail signal processing from results. While the wavelet analysis and experimental results are compared and found in good agreement with the experimental results. (authors)

  17. Three-dimensional detonation cellular structures in rectangular ducts using an improved CESE scheme

    KAUST Repository

    Shen, Yang; Shen, Hua; Liu, Kai Xin; Chen, Pu; Zhang, De Liang

    2016-01-01

    The three-dimensional premixed H2-O2 detonation propagation in rectangular ducts is simulated using an in-house parallel detonation code based on the second-order space–time conservation element and solution element (CE/SE) scheme. The simulation reproduces three typical cellular structures by setting appropriate cross-sectional size and initial perturbation in square tubes. As the cross-sectional size decreases, critical cellular structures transforming the rectangular or diagonal mode into the spinning mode are obtained and discussed in the perspective of phase variation as well as decreasing of triple point lines. Furthermore, multiple cellular structures are observed through examples with typical aspect ratios. Utilizing the visualization of detailed three-dimensional structures, their formation mechanism is further analyzed.

  18. Mechanical behavior analysis on electrostatically actuated rectangular microplates

    International Nuclear Information System (INIS)

    Li, Zhikang; Zhao, Libo; Jiang, Zhuangde; Ye, Zhiying; Zhao, Yulong; Dai, Lu

    2015-01-01

    Microplates are widely used in various MEMS devices based on electrostatic actuation such as MEMS switches, micro pumps and capacitive micromachined ultrasonic transducers (CMUTs). Accurate predictions for the mechanical behavior of the microplate under electrostatic force are important not only for the design and optimization of these electrostatic devices but also for their operation. This paper presents a novel reduced-order model for electrostatically actuated rectangular and square microplates with a new method to treat the nonlinear electrostatic force. The model was developed using Galerkin method which turned the partial-differential equation governing the microplates into an ordinary equation system. Using this model and cosine-like deflection functions, explicit expressions were established for the deflection and pull-in voltage of the rectangular and square microplates. The theoretical results were well validated with the finite element method simulations and experimental data of literature. The expressions for the deflection analysis are able to predict the deflection up to the pull-in position with an error less than 5.0%. The expressions for the pull-in voltage analysis can determine the pull-in voltages with errors less than 1.0%. Additionally, the method to calculate the capacitance variation of the electrostatically actuated microplates was proposed. These theoretical analyses are helpful for design and optimization of electrostatically actuated microdevices. (paper)

  19. Cold plate

    Energy Technology Data Exchange (ETDEWEB)

    Marroquin, Christopher M.; O' Connell, Kevin M.; Schultz, Mark D.; Tian, Shurong

    2018-02-13

    A cold plate, an electronic assembly including a cold plate, and a method for forming a cold plate are provided. The cold plate includes an interface plate and an opposing plate that form a plenum. The cold plate includes a plurality of active areas arranged for alignment over respective heat generating portions of an electronic assembly, and non-active areas between the active areas. A cooling fluid flows through the plenum. The plenum, at the non-active areas, has a reduced width and/or reduced height relative to the plenum at the active areas. The reduced width and/or height of the plenum, and exterior dimensions of cold plate, at the non-active areas allow the non-active areas to flex to accommodate surface variations of the electronics assembly. The reduced width and/or height non-active areas can be specifically shaped to fit between physical features of the electronics assembly.

  20. Design and fabrication of circular and rectangular components for electron-cyclotron-resonant heating of tandem mirror experiment-upgrade

    International Nuclear Information System (INIS)

    Felker, B.; Calderon, M.O.; Chargin, A.K.

    1983-01-01

    The electron-cyclotron-resonant heating (ECRH) systems of rectangular waveguides on Tandem Mirror Experiment-Upgrade (TMX-U) operated with a overall efficiency of 50%, each system using a 28-GHz, 200-kW pulsed gyrotron. We designed and built four circular-waveguide systems with greater efficiency and greater power-handling capabilities to replace the rectangular waveguides. Two of these circular systems, at the 5-kG second-harmonic heating locations, have a total transmission efficiency of >90%. The two systems at the 10-kG fundamental heating locations have a total transmission efficiency of 80%. The difference in efficiency is due to the additional components required to launch the microwaves in the desired orientation and polarization with respect to magnetic-field lines at the 10-kG points. These systems handle the total power available from each gyrotron but do not have the arcing limitation problem of the rectangular waveguide. Each system requires several complex components. The overall physical layout and the design considerations for the rectangular and circular waveguide components are described here

  1. Design and fabrication of circular and rectangular components for electron-cyclotron-resonant heating of tandem mirror experiment-upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Felker, B.; Calderon, M.O.; Chargin, A.K.; Coffield, F.E.; Lang, D.D.; Rubert, R.R.; Pedrotti, L.R.; Stallard, B.W.; Gallagher, N.C. Jr.; Sweeney, D.W.

    1983-11-18

    The electron-cyclotron-resonant heating (ECRH) systems of rectangular waveguides on Tandem Mirror Experiment-Upgrade (TMX-U) operated with a overall efficiency of 50%, each system using a 28-GHz, 200-kW pulsed gyrotron. We designed and built four circular-waveguide systems with greater efficiency and greater power-handling capabilities to replace the rectangular waveguides. Two of these circular systems, at the 5-kG second-harmonic heating locations, have a total transmission efficiency of >90%. The two systems at the 10-kG fundamental heating locations have a total transmission efficiency of 80%. The difference in efficiency is due to the additional components required to launch the microwaves in the desired orientation and polarization with respect to magnetic-field lines at the 10-kG points. These systems handle the total power available from each gyrotron but do not have the arcing limitation problem of the rectangular waveguide. Each system requires several complex components. The overall physical layout and the design considerations for the rectangular and circular waveguide components are described here.

  2. Behavior of thin rectangular ANCF shell elements in various mesh configurations

    DEFF Research Database (Denmark)

    Hyldahl, Per; Mikkola, Aki M.; Balling, Ole

    2014-01-01

    a thorough review of three available formulations, they are used in three different convergence studies. Initially a reference study is conducted to determine how the ANCF performs in an uniform and rectangular mesh. Subsequently, the ANCF methods sensitivity to irregular mesh is investigated and finally...

  3. Research on the comparison of extension mechanism of cellular automaton based on hexagon grid and rectangular grid

    Science.gov (United States)

    Zhai, Xiaofang; Zhu, Xinyan; Xiao, Zhifeng; Weng, Jie

    2009-10-01

    Historically, cellular automata (CA) is a discrete dynamical mathematical structure defined on spatial grid. Research on cellular automata system (CAS) has focused on rule sets and initial condition and has not discussed its adjacency. Thus, the main focus of our study is the effect of adjacency on CA behavior. This paper is to compare rectangular grids with hexagonal grids on their characteristics, strengths and weaknesses. They have great influence on modeling effects and other applications including the role of nearest neighborhood in experimental design. Our researches present that rectangular and hexagonal grids have different characteristics. They are adapted to distinct aspects, and the regular rectangular or square grid is used more often than the hexagonal grid. But their relative merits have not been widely discussed. The rectangular grid is generally preferred because of its symmetry, especially in orthogonal co-ordinate system and the frequent use of raster from Geographic Information System (GIS). However, in terms of complex terrain, uncertain and multidirectional region, we have preferred hexagonal grids and methods to facilitate and simplify the problem. Hexagonal grids can overcome directional warp and have some unique characteristics. For example, hexagonal grids have a simpler and more symmetric nearest neighborhood, which avoids the ambiguities of the rectangular grids. Movement paths or connectivity, the most compact arrangement of pixels, make hexagonal appear great dominance in the process of modeling and analysis. The selection of an appropriate grid should be based on the requirements and objectives of the application. We use rectangular and hexagonal grids respectively for developing city model. At the same time we make use of remote sensing images and acquire 2002 and 2005 land state of Wuhan. On the base of city land state in 2002, we make use of CA to simulate reasonable form of city in 2005. Hereby, these results provide a proof of

  4. Numerical study on rectangular microhollow cathode discharge

    International Nuclear Information System (INIS)

    He Shoujie; Ouyang Jiting; He Feng; Li Shang

    2011-01-01

    Rectangular microhollow cathode discharge in argon is investigated by using two-dimensional time-dependent self-consistent fluid model. The electric potential, electric field, particle density, and mean electron energy are calculated. The results show that hollow cathode effect can be onset in the present configuration, with strong electric field and high mean electron energy in the cathode fall while high density and quasineutral plasma in the negative glow. The potential well and electric filed reversal are formed in the negative glow region. It is suggested that the presence of large electron diffusion flux necessitates the field reversal and potential well.

  5. Effect on two-phase flow frictional pressure drop characteristic in narrow rectangular channel at fluctuant condition

    International Nuclear Information System (INIS)

    Li Changwei; Cao Xiaxin; Sun Licheng; Jin Guangyuan

    2013-01-01

    Based on the data of two-phase flow in narrow rectangular channel, the influence of the two-phase flow friction characteristic under the different fluctuant states was analyzed. Through analyzing the experimental data, it is shown that the fluctuant amplitude of the friction pressure drop is affected slightly by the fluctuant period in narrow rectangular channel, but the frequency of the friction pressure drop fluctuation is changed. However, the change of fluctuant period is of little effect on the average frictional pressure drop. Comparing the φ l 2 (φ g 2 )-X variation curves at static condition with the ones at fluctuant condition, using the L-M method, it's found that the two phase frictional pressure drop in the narrow rectangular channel under the fluctuant state can be calculated by the φ l 2 (φ g 2 )-X variation curve at static condition. (authors)

  6. Study of gas-water flow in horizontal rectangular channels

    Science.gov (United States)

    Chinnov, E. A.; Ron'shin, F. V.; Kabov, O. A.

    2015-09-01

    The two-phase flow in the narrow short horizontal rectangular channels 1 millimeter in height was studied experimentally. The features of formation of the two-phase flow were studied in detail. It is shown that with an increase in the channel width, the region of the churn and bubble regimes increases, compressing the area of the jet flow. The areas of the annular and stratified flow patterns vary insignificantly.

  7. Regimes of Vorticity in the Wake of a Rectangular Vortex Generator

    DEFF Research Database (Denmark)

    Velte, Clara Marika; Okulov, Valery; Hansen, Martin Otto Laver

    2011-01-01

    This paper concerns the study of the secondary structures generated in the wake of a wall mounted rectangular vane, commonly referred to as a vortex generator. The study has been conducted by Stereoscopic PIV measurements in a wind tunnel and supplementary flow visualizations in a water channel...

  8. Experimental and Theoretical Analysis for a Fluid-Loaded, Simply Supported Plate Covered by a Damping and Decoupling Composite Acoustic Coating

    Directory of Open Access Journals (Sweden)

    Baihua Yuan

    2017-01-01

    Full Text Available This work presents a vibroacoustic response model for a fluid-loaded, simply supported rectangular plate covered by a composite acoustic coating consisting of damping and decoupling layers. The model treated the damping layer and base plate as a unified whole under pure bending moments and the decoupling layer as a three-dimensional, isotropic, linear elastic solid. The validity of the model was verified by both numerical analysis and experiments and was shown to accurately extend previous studies that were limited to a plate covered by a single damping or decoupling layer with an evaluation confined solely to numerical analysis. The trends of the numerical and experimental results are generally consistent, with some differences due to the influences of water pressure and the frequency dependence of the material parameters, which are not taken into account by the numerical analysis. Both experimental and numerical results consistently show that the radiated noise reduction effect of the composite coating is superior to that of single-type coatings, which is attributed to the fact that the composite coating combines the merits of both the high vibration suppression performance of the damping layer and the superior vibration isolation performance of the decoupling layer.

  9. Size effect of the elastic modulus of rectangular nanobeams: Surface elasticity effect

    International Nuclear Information System (INIS)

    Yao Hai-Yan; Fan Wen-Liang; Yun Guo-Hong

    2013-01-01

    The size-dependent elastic property of rectangular nanobeams (nanowires or nanoplates) induced by the surface elasticity effect is investigated by using a developed modified core-shell model. The effect of surface elasticity on the elastic modulus of nanobeams can be characterized by two surface related parameters, i.e., inhomogeneous degree constant and surface layer thickness. The analytical results show that the elastic modulus of the rectangular nanobeam exhibits a distinct size effect when its characteristic size reduces below 100 nm. It is also found that the theoretical results calculated by a modified core-shell model have more obvious advantages than those by other models (core-shell model and core-surface model) by comparing them with relevant experimental measurements and computational results, especially when the dimensions of nanostructures reduce to a few tens of nanometers. (condensed matter: structural, mechanical, and thermal properties)

  10. Sound absorption effects in a rectangular enclosure with the foamed aluminum sheet absorber

    International Nuclear Information System (INIS)

    Oh, Jae Eung; Chung, Jin Tai; Kim, Sang Hun; Chung, Kyung Ryul

    1998-01-01

    For the purpose of finding out the optimal thickness of sound absorber and the sound absorption effects due to the selected thickness at an interested frequency range, the analytical study identifies the interior and exterior sound field characteristics of a rectangular enclosure with foamed aluminum lining and the experimental verification is performed with random noise input. By using a two-microphone impedance tube, we measure experimentally the absorption coefficient and the impedance of simple sound absorbing materials. Measured acoustical parameters of the test samples are applied to the theoretical analysis to predict sound pressure field in the cavity. The sound absorption effects from measurements are compared to predicted ones in both cases with and without foamed aluminum lining in the cavity of the rectangular enclosure

  11. Study on critical heat flux based on wavelet transform in rectangular narrow channels

    International Nuclear Information System (INIS)

    Zhou Tao; Ju Zhongyun; Zhang Lei; Li Jingjing; Sheng Cheng; Xiao Zejun

    2014-01-01

    Critical heat flux is very important for the safety of nuclear reactor, and observing temperature rise rate is a feasible method. The wavelet transform is used to analyze the CHF temperature rise curves in rectangular narrow channels, which can remove relative weaker interference and effectively judge CHF. Rectangular narrow channel can strengthen heat transfer and reduce CHF, whose characteristics are proved by temperature rise curves analyzed by wavelet transform. Respectively applying Daubechies function and Haar function is to guarantee the accuracy of the wavelet analysis, and Daubechies function is more accurate than Haar function in the detail signal processing from results. While the wavelet analysis and experimental results are compared and found in good agreement with the experimental results. (authors)

  12. Three-dimensional detonation cellular structures in rectangular ducts using an improved CESE scheme

    International Nuclear Information System (INIS)

    Shen Yang; Liu Kai-Xin; Chen Pu; Shen Hua; Zhang De-Liang

    2016-01-01

    The three-dimensional premixed H 2 -O 2 detonation propagation in rectangular ducts is simulated using an in-house parallel detonation code based on the second-order space–time conservation element and solution element (CE/SE) scheme. The simulation reproduces three typical cellular structures by setting appropriate cross-sectional size and initial perturbation in square tubes. As the cross-sectional size decreases, critical cellular structures transforming the rectangular or diagonal mode into the spinning mode are obtained and discussed in the perspective of phase variation as well as decreasing of triple point lines. Furthermore, multiple cellular structures are observed through examples with typical aspect ratios. Utilizing the visualization of detailed three-dimensional structures, their formation mechanism is further analyzed. (paper)

  13. Rectangular illumination using a secondary optics with cylindrical lens for LED street light.

    Science.gov (United States)

    Chen, Hsi-Chao; Lin, Jun-Yu; Chiu, Hsuan-Yi

    2013-02-11

    The illumination pattern of an LED street light is required to have a rectangular distribution at a divergence-angle ratio of 7:3 for economical illumination. Hence, research supplying a secondary optics with two cylindrical lenses was different from free-form curvature for rectangular illumination. The analytical solution for curvatures with different ratio rectangles solved this detail by light tracing and boundary conditions. Similarities between the experiments and the simulation for a single LED and a 9-LED module were analyzed by Normalized Cross Correlation (NCC), and the error rate was studied by the Root Mean Square (RMS). The tolerance of position must be kept under ± 0.2 mm in the x, y and z directions to ensure that the relative illumination is over 99%.

  14. Global field synchronization in gamma range of the sleep EEG tracks sleep depth: Artifact introduced by a rectangular analysis window.

    Science.gov (United States)

    Rusterholz, Thomas; Achermann, Peter; Dürr, Roland; Koenig, Thomas; Tarokh, Leila

    2017-06-01

    Investigating functional connectivity between brain networks has become an area of interest in neuroscience. Several methods for investigating connectivity have recently been developed, however, these techniques need to be applied with care. We demonstrate that global field synchronization (GFS), a global measure of phase alignment in the EEG as a function of frequency, must be applied considering signal processing principles in order to yield valid results. Multichannel EEG (27 derivations) was analyzed for GFS based on the complex spectrum derived by the fast Fourier transform (FFT). We examined the effect of window functions on GFS, in particular of non-rectangular windows. Applying a rectangular window when calculating the FFT revealed high GFS values for high frequencies (>15Hz) that were highly correlated (r=0.9) with spectral power in the lower frequency range (0.75-4.5Hz) and tracked the depth of sleep. This turned out to be spurious synchronization. With a non-rectangular window (Tukey or Hanning window) these high frequency synchronization vanished. Both, GFS and power density spectra significantly differed for rectangular and non-rectangular windows. Previous papers using GFS typically did not specify the applied window and may have used a rectangular window function. However, the demonstrated impact of the window function raises the question of the validity of some previous findings at higher frequencies. We demonstrated that it is crucial to apply an appropriate window function for determining synchronization measures based on a spectral approach to avoid spurious synchronization in the beta/gamma range. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Investigation of process induced warpage for pultrusion of a rectangular hollow profile

    DEFF Research Database (Denmark)

    Baran, Ismet; Hattel, Jesper Henri; Akkerman, Remko

    2015-01-01

    A novel thermo-chemical–mechanical analysis of the pultrusion process is presented. A process simulation is performed for an industrially pultruded rectangular hollow profile containing both unidirectional (UD) roving and continuous filament mat (CFM) layers. The reinforcements are impregnated...

  16. Polydisperse particle-driven gravity currents in non-rectangular cross section channels

    Science.gov (United States)

    Zemach, T.

    2018-01-01

    We consider a high-Reynolds-number gravity current generated by polydisperse suspension of n types of particles distributed in a fluid of density ρi. Each class of particles in suspension has a different settling velocity. The current propagates along a channel of non-rectangular cross section into an ambient fluid of constant density ρa. The bottom and top of the channel are at z = 0, H, and the cross section is given by the quite general form -f1(z) ≤ y ≤ f2(z) for 0 ≤ z ≤ H. The flow is modeled by the one-layer shallow-water equations obtained for the time-dependent motion. We solve the problem by a finite-difference numerical code to present typical height h, velocity u, and mass fractions of particle (concentrations) (ϕ( j), j = 1, …, n) profiles. The runout length of suspensions in channels of power-law cross sections is analytically predicted using a simplified depth-averaged "box" model. We demonstrate that any degree of polydispersivity adds to the runout length of the currents, relative to that of equivalent monodisperse currents with an average settling velocity. The theoretical predictions are supported by the available experimental data. The present approach is a significant generalization of the particle-driven gravity current problem: on the one hand, now the monodisperse current in non-rectangular channels is a particular case of n = 1. On the other hand, the classical formulation of polydisperse currents for a rectangular channel is now just a particular case, f(z) = const., in the wide domain of cross sections covered by this new model.

  17. Fast damage imaging using the time-reversal technique in the frequency–wavenumber domain

    International Nuclear Information System (INIS)

    Zhu, R; Huang, G L; Yuan, F G

    2013-01-01

    The time-reversal technique has been successfully used in structural health monitoring (SHM) for quantitative imaging of damage. However, the technique is very time-consuming when it is implemented in the time domain. In this paper, we study the technique in the frequency–wavenumber (f–k) domain for fast real-time imaging of multiple damage sites in plates using scattered flexural plate waves. Based on Mindlin plate theory, the time reversibility of dispersive flexural waves in an isotropic plate is theoretically investigated in the f–k domain. A fast damage imaging technique is developed by using the cross-correlation between the back-propagated scattered wavefield and the incident wavefield in the frequency domain. Numerical simulations demonstrate that the proposed technique cannot only localize multiple damage sites but also potentially identify their sizes. Moreover, the time-reversal technique in the f–k domain is about two orders of magnitude faster than the method in the time domain. Finally, experimental testing of an on-line SHM system with a sparse piezoelectric sensor array is conducted for fast multiple damage identification using the proposed technique. (paper)

  18. Effect of aspect ratio in free-swimming plunging flexible plates

    Science.gov (United States)

    Yeh, Peter; Alexeev, Alexander

    2015-11-01

    Using three dimensional fully-coupled fluid-structure interaction simulations, we investigate the free swimming of plunging elastic rectangular plates with aspect ratios ranging from 0.5 to 5 in a viscous fluid with Reynolds number 250. We find that maximum velocity occurs near the first natural frequency regardless of aspect ratio, while the maximum swimming economy occurs away from the first natural frequency and corresponds to a specific swimmer bending pattern characterized by reduced displacement of the swimmer's center of mass. Furthermore, we find that swimmers with wider span are both faster and more economical than narrow swimmers. These faster speeds are due to decreased drag for low aspect ratio plunging swimmers, which is in agreement with a recently proposed vortex-induced drag model that suggests that the smaller relative size of side vortices in low aspect ratio swimmers creates less drag per unit width. Our results are useful for the design of small autonomous micro-swimming devices and also provide insights on the physics of aquatic locomotion using oscillating fins.

  19. Modeling on bubbly to churn flow pattern transition for vertical upward flows in narrow rectangular channel

    International Nuclear Information System (INIS)

    Wang Yanlin; Chen Bingde; Huang Yanping; Wang Junfeng

    2011-01-01

    A theoretical model was developed to predict the bubbly to churn flow pattern transition for vertical upward flows in narrow rectangular channel. The model was developed based on the imbalance theory of Helmholtz and some reasonable assumptions. The maximum ideal bubble in narrow rectangular channel and the thermal hydraulics boundary condition leading to bubbly flow to churn flow pattern transition was calculated. The model was validated by experimental data from previous researches. Comparison between predicted result and experimental result shows a reasonable good agreement. (author)

  20. The time of discrete spectrum identical particles tunneling at their simultaneous passing over rectangular quantum barrier

    International Nuclear Information System (INIS)

    Martsenyuk, L.S.

    2010-01-01

    Research of influence of exchange interaction of identical particles for the time of their simultaneous tunneling through a rectangular quantum barrier is lead. The account of identity leads to necessity of symmetrisation of wave function owing to what in the formula describing interaction of two particles, arises an additional element. In result the parameters of tunneling, including time of tunneling change. Time of tunneling is calculated from the formula received in work from the size of exchange interaction of two particles simultaneously crossing a rectangular quantum barrier.

  1. A study on liquid lithium flow in rectangular duck perpendicular to a intense magnetic field

    International Nuclear Information System (INIS)

    Shen Xiuzhong; Chen Ke; Liu Yang; Zhang Qinshun

    2001-01-01

    A research on high-speed liquid-metal lithium flow through a non-expanding rectangular duck under uniform intense magnetic field is presented. A equations set with Poisson equation and Helmholtz equation, which control the electrical field and flow field respectively, has been deduced by analysis and PHsolver, a program to solve the equations set, has also been finished. The current density distribution and flow field in the non-expanding rectangular channel with intense magnetic field have been obtained from PHsolver by applying the wall-function in the boundary wall. The velocity profile in the duck appears M-shaped

  2. Analytical study of a reversed-field pinch with rectangular cross section

    International Nuclear Information System (INIS)

    Zhang Peng

    1990-01-01

    An analyic solution of the force-free equation for a toroidal configuration of rectangular cross section is presented. It is shown that the critical value of contraction ratio for the appearance of a reversed field as well as of the ohmic current increases as the elongation of the cross section increases

  3. The Effects of a Rectangular Rapid-Flashing Beacon on Vehicle Speed

    Science.gov (United States)

    VanWagner, Michelle; Van Houten, Ron; Betts, Brian

    2011-01-01

    In 2008, nearly 31% of vehicle fatalities were related to failure to adhere to safe vehicle speeds (National Highway Traffic Safety Administration [NHTSA], 2009). The current study evaluated the effect of a rectangular rapid-flashing beacon (RRFB) triggered by excessive speed on vehicle speed using a combined alternating treatments and reversal…

  4. Plate-fin array cooling using a finger-like piezoelectric fan

    International Nuclear Information System (INIS)

    Shyu, Jin-Cherng; Syu, Jhih-Zong

    2014-01-01

    In this study, the heat transfer of a plate-fin array cooled by a vibrating finger-like piezoelectric fan comprising four flexible rectangular blades was investigated. The results indicated that the heat transfer enhancement of the fin array cooled by a vibrating piezoelectric fan at x/L = 0.5 and H = 5 mm ranged between 1.5 and 3.3, regardless of the fin array orientation. However, the heat transfer enhancement caused by a fan being placed at either edge of the fin array yielded a dissimilar result between both of the fin array orientations because of the superimposed effects of the boundary layer development and the air flow induced by the fan. This dissimilarity was especially noticeable when the piezoelectric fan was composed of aluminum blades to accommodate the moderate Reynolds number. In addition to the Reynolds number, the ratio of the fan blade vibration envelope to the source area determined the Nu number of the piezoelectric fan-cooled fin array. This design enhanced the fin array heat transfer and reduced cooler volume by embedding multiple vibrating beams into the fin array. -- Highlights: • Heat transfer of a piezoelectric fan-cooled plate-fin array was investigated. • Effects of fan position, fan height and fan material on heat transfer were examined. • Similar heat transfer enhancement range was shown for both fin array orientations. • Fin heat transfer with a running Al fan at x = 0 was higher than that at x = 0.25L. • Besides fan Reynolds number, the area ratio also determined Nu of the fin array

  5. Radiation shielding plate

    International Nuclear Information System (INIS)

    Kobayashi, Torakichi; Sugawara, Takeo.

    1983-01-01

    Purpose: To reduce the weight and stabilize the configuration of a radiation shielding plate which is used in close contact with an object to be irradiated with radiation rays. Constitution: The radiation shielding plate comprises a substrate made of lead glass and a metallic lead coating on the surface of the substrate by means of plating, vapor deposition or the like. Apertures for permeating radiation rays are formed to the radiation shielding plate. Since the shielding plate is based on a lead glass plate, a sufficient mechanical strength can be obtained with a thinner structure as compared with the conventional plate made of metallic lead. Accordingly, if the shielding plate is disposed on a soft object to be irradiated with radiation rays, the object and the plate itself less deform to obtain a radiation irradiation pattern with distinct edges. (Moriyama, K.)

  6. Effect of aspect ratio on the laminar-to-turbulent transition in rectangular channel

    International Nuclear Information System (INIS)

    Wang Chang; Gao Puzhen; Tan Sichao; Xu Chao

    2012-01-01

    Highlights: ► Effect of aspect ratio on the transition Reynolds number in rectangular channel is studied. ► Prediction correlation for transition Reynolds number is proposed. ► The initiation location of flow transition is studied. - Abstract: The critical Reynolds number of the laminar-to-turbulent transition in the rectangular channel is investigated based on the energy gradient method. The results show that the critical Reynolds number decreases with the increasing aspect ratio. However, the relative location of laminar breakdown does not migrate significantly with the variation of the aspect ratio. In addition, a theoretical correlation as a function of the aspect ratio is proposed to calculate the transition Reynolds number, and the predicted values are in good agreement with the experimental data obtained in the published literatures.

  7. Forward and backward THz-wave difference frequency generations from a rectangular nonlinear waveguide.

    Science.gov (United States)

    Huang, Yen-Chieh; Wang, Tsong-Dong; Lin, Yen-Hou; Lee, Ching-Han; Chuang, Ming-Yun; Lin, Yen-Yin; Lin, Fan-Yi

    2011-11-21

    We report forward and backward THz-wave difference frequency generations at 197 and 469 μm from a PPLN rectangular crystal rod with an aperture of 0.5 (height in z) × 0.6 (width in y) mm(2) and a length of 25 mm in x. The crystal rod appears as a waveguide for the THz waves but as a bulk material for the optical mixing waves near 1.54 μm. We measured enhancement factors of 1.6 and 1.8 for the forward and backward THz-wave output powers, respectively, from the rectangular waveguide in comparison with those from a PPLN slab waveguide of the same length, thickness, and domain period under the same pump and signal intensity of 100 MW/cm(2). © 2011 Optical Society of America

  8. Plating on difficult-to-plate metals: what's new

    International Nuclear Information System (INIS)

    Wiesner, H.J.

    1980-01-01

    Some of the changes since 1970 in procedures for plating on such materials as titanium, molybdenum, silicon, aluminum, and gallium arsenide are summarized. While basic procedures for plating some of these materials were developed as many as 30 to 40 years ago, changes in the end uses of the plated products have necessitated new plating processes. In some cases, vacuum techniques - such as ion bombardment, ion implantation, and vacuum metallization - have been introduced to improve the adhesion of electrodeposits. In other cases, these techniques have been used to deposit materials upon which electrodeposits are required

  9. Effect of plate shapes in orifice plate type flowmeters

    International Nuclear Information System (INIS)

    Moeller, S.V.

    1984-01-01

    The study of unusual plate shapes in orifice plate type flowmeters is presented, with a view to providing data for the substitution of the plate with one centered circular orifice in those applications where its use is not possible. For this purpose, six pairs of plates with different forms, with and without chamfered edges, were made and tested in a closed water loop. Results show that, generally, the use of chamfers improves the results and, in the case of perforated and slotlike orificed plates, the narrow-ness of the fluid passage tends to make unnecessary its use. (Author) [pt

  10. Plating laboratory

    International Nuclear Information System (INIS)

    Seamster, A.G.; Weitkamp, W.G.

    1984-01-01

    The lead plating of the prototype resonator has been conducted entirely in the plating laboratory at SUNY Stony Brook. Because of the considerable cost and inconvenience in transporting personnel and materials to and from Stony Brook, it is clearly impractical to plate all the resonators there. Furthermore, the high-beta resonator cannot be accommodated at Stony Brook without modifying the set up there. Consequently the authors are constructing a plating lab in-house

  11. Bandwidth Study of the Microwave Reflectors with Rectangular Corrugations

    Science.gov (United States)

    Zhang, Liang; He, Wenlong; Donaldson, Craig R.; Cross, Adrian W.

    2016-09-01

    The mode-selective microwave reflector with periodic rectangular corrugations in the inner surface of a circular metallic waveguide is studied in this paper. The relations between the bandwidth and reflection coefficient for different numbers of corrugation sections were studied through a global optimization method. Two types of reflectors were investigated. One does not consider the phase response and the other does. Both types of broadband reflectors operating at W-band were machined and measured to verify the numerical simulations.

  12. Air-water upward flow in prismatic channel of rectangular base

    International Nuclear Information System (INIS)

    Carvalho Tofani, P. de.

    1984-01-01

    Experiments had carried out to investigate the two-phase upward air-water flow structure, in a rectangular test section, by using independent measuring techniques, which comprise direct viewing and photography, electrical probes and gamma-ray attenuation. Flow pattern maps and correlations for flow pattern transitions, void fraction profiles, liquid film thickness and superficial average void fraction are proposed and compared to available data. (Author) [pt

  13. Experiments of dike-induced deformation: Insights on the long-term evolution of divergent plate boundaries

    KAUST Repository

    Trippanera, D.

    2015-10-22

    The shallow transport of magma occurs through dikes causing surface deformation. Our understanding of the effects of diking at the surface is limited, especially on the long term, for repeated intrusive episodes. We use analogue models to study the upper crustal deformation induced by dikes. We insert metal plates within cohesive sand with three setups: in setup A, the intrusion rises upward with constant thickness and in setups B and C, the intrusion thickens at a fixed depth, with final rectangular (setup B) or triangular (setup C) shape in section. Setup A creates a doming delimited by reverse faults, with secondary apical graben, without close correspondence in nature. In setups B and C, a depression flanked by two uplifted areas is bordered by inward dipping normal faults propagating downward and, for deeper intrusions in setup B, also by inner faults, reverse at the surface; this deformation is similar to what is observed in nature, suggesting a consistent physical behavior. Dikes in nature initially propagate developing a mode I fracture at the tip, subsequently thickened by magma intrusion, without any host rock translation in the propagation direction (as in setup A). The deformation pattern in setups B and C depends on the intrusion depth and thickness, consistently to what is observed along divergent plate boundaries. The early deformation in setups B and C is similar to that from a single rifting episode (i.e., Lakagigar, Iceland, and Dabbahu, Afar), whereas the late stages resemble the structure of mature rifts (i.e., Krafla, Iceland), confirming diking as a major process in shaping divergent plate boundaries.

  14. From the rectangular to the quincunx Gabor lattice via fractional Fourier transformation

    NARCIS (Netherlands)

    Bastiaans, M.J.; Leest, van A.J.

    1998-01-01

    Transformations of Gabor lattices have been associated with operations on the window functions that arise in Gabor theory. In particular it has been shown that transformation from a rectangular to a quincunx lattice can be associated with fractional Fourier transformation. Since a Gaussian function,

  15. One-dimensional acoustic standing waves in rectangular channels for flow cytometry.

    Science.gov (United States)

    Austin Suthanthiraraj, Pearlson P; Piyasena, Menake E; Woods, Travis A; Naivar, Mark A; Lόpez, Gabriel P; Graves, Steven W

    2012-07-01

    Flow cytometry has become a powerful analytical tool for applications ranging from blood diagnostics to high throughput screening of molecular assemblies on microsphere arrays. However, instrument size, expense, throughput, and consumable use limit its use in resource poor areas of the world, as a component in environmental monitoring, and for detection of very rare cell populations. For these reasons, new technologies to improve the size and cost-to-performance ratio of flow cytometry are required. One such technology is the use of acoustic standing waves that efficiently concentrate cells and particles to the center of flow channels for analysis. The simplest form of this method uses one-dimensional acoustic standing waves to focus particles in rectangular channels. We have developed one-dimensional acoustic focusing flow channels that can be fabricated in simple capillary devices or easily microfabricated using photolithography and deep reactive ion etching. Image and video analysis demonstrates that these channels precisely focus single flowing streams of particles and cells for traditional flow cytometry analysis. Additionally, use of standing waves with increasing harmonics and in parallel microfabricated channels is shown to effectively create many parallel focused streams. Furthermore, we present the fabrication of an inexpensive optical platform for flow cytometry in rectangular channels and use of the system to provide precise analysis. The simplicity and low-cost of the acoustic focusing devices developed here promise to be effective for flow cytometers that have reduced size, cost, and consumable use. Finally, the straightforward path to parallel flow streams using one-dimensional multinode acoustic focusing, indicates that simple acoustic focusing in rectangular channels may also have a prominent role in high-throughput flow cytometry. Copyright © 2012 Elsevier Inc. All rights reserved.

  16. Lattice Boltzmann Simulation of the Hydrodynamic Entrance Region of Rectangular Microchannels in the Slip Regime

    Directory of Open Access Journals (Sweden)

    Niya Ma

    2018-02-01

    Full Text Available Developing a three-dimensional laminar flow in the entrance region of rectangular microchannels has been investigated in this paper. When the hydrodynamic development length is the same magnitude as the microchannel length, entrance effects have to be taken into account, especially in relatively short ducts. Simultaneously, there are a variety of non-continuum or rarefaction effects, such as velocity slip and temperature jump. The available data in the literature appearing on this issue is quite limited, the available study is the semi-theoretical approximate model to predict pressure drop of developing slip flow in rectangular microchannels with different aspect ratios. In this paper, we apply the lattice Boltzmann equation method (LBE to investigate the developing slip flow through a rectangular microchannel. The effects of the Reynolds number (1 < Re < 1000, channel aspect ratio (0 < ε < 1, and Knudsen number (0.001 < Kn < 0.1 on the dimensionless hydrodynamic entrance length, and the apparent friction factor, and Reynolds number product, are examined in detail. The numerical solution of LBM can recover excellent agreement with the available data in the literature, which proves its accuracy in capturing fundamental fluid characteristics in the slip-flow regime.

  17. Dual cameras acquisition and display system of retina-like sensor camera and rectangular sensor camera

    Science.gov (United States)

    Cao, Nan; Cao, Fengmei; Lin, Yabin; Bai, Tingzhu; Song, Shengyu

    2015-04-01

    For a new kind of retina-like senor camera and a traditional rectangular sensor camera, dual cameras acquisition and display system need to be built. We introduce the principle and the development of retina-like senor. Image coordinates transformation and interpolation based on sub-pixel interpolation need to be realized for our retina-like sensor's special pixels distribution. The hardware platform is composed of retina-like senor camera, rectangular sensor camera, image grabber and PC. Combined the MIL and OpenCV library, the software program is composed in VC++ on VS 2010. Experience results show that the system can realizes two cameras' acquisition and display.

  18. HIGH QUALITY FACADE SEGMENTATION BASED ON STRUCTURED RANDOM FOREST, REGION PROPOSAL NETWORK AND RECTANGULAR FITTING

    Directory of Open Access Journals (Sweden)

    K. Rahmani

    2018-05-01

    Full Text Available In this paper we present a pipeline for high quality semantic segmentation of building facades using Structured Random Forest (SRF, Region Proposal Network (RPN based on a Convolutional Neural Network (CNN as well as rectangular fitting optimization. Our main contribution is that we employ features created by the RPN as channels in the SRF.We empirically show that this is very effective especially for doors and windows. Our pipeline is evaluated on two datasets where we outperform current state-of-the-art methods. Additionally, we quantify the contribution of the RPN and the rectangular fitting optimization on the accuracy of the result.

  19. Measurement on the cavitating vortex shedding behind rectangular obstacles

    International Nuclear Information System (INIS)

    Hegedus, F; Hos, C; Pandula, Z; Kullmann, L

    2010-01-01

    Measurement results on the cavitating vortex shedding behind sharp-edged rectangular bodies are presented, intended to provide benchmark cases for the validation of unsteady cavitation models of CFD codes. Rectangular bodies of increasing aspect ratio (1, 2, 3 and 4) were used with a constant 25mm height (12.5% blockage ratio). The water velocity in the 0.2x0.05m test section of the channel was varied between 1 and 12 m/s resulting in a Reynolds number in the range of (0.4-3.5)x105. Pressure signals were measured at several locations, notably in the wake. Dominant frequencies and Strouhal numbers are reported from cavitation-free flow (classic von Karman vortex shedding) up to supercavitation as a function of the free-stream Reynolds number. The results are in good agreement with the literature in case of the square cylinder. We experienced a slight increase of the dominant Strouhal number with increasing aspect ratio. This result is somewhat inconsistent with the literature, in which a fall of the Strouhal number can be observed at side ratio 2. This may be the consequence of the different ranges of Reynolds numbers. It was also found that between the inception of cavitation and the formation of supercavitation the Strouhal number is not affected by cavitation.

  20. Measurement on the cavitating vortex shedding behind rectangular obstacles

    Energy Technology Data Exchange (ETDEWEB)

    Hegedus, F; Hos, C; Pandula, Z; Kullmann, L, E-mail: hegedusf@hds.bme.h [Department of Hydrodynamic Systems, Budapest University of Technology and Economics Muegyetem rkp. 1, Budapest 1111 (Hungary)

    2010-08-15

    Measurement results on the cavitating vortex shedding behind sharp-edged rectangular bodies are presented, intended to provide benchmark cases for the validation of unsteady cavitation models of CFD codes. Rectangular bodies of increasing aspect ratio (1, 2, 3 and 4) were used with a constant 25mm height (12.5% blockage ratio). The water velocity in the 0.2x0.05m test section of the channel was varied between 1 and 12 m/s resulting in a Reynolds number in the range of (0.4-3.5)x105. Pressure signals were measured at several locations, notably in the wake. Dominant frequencies and Strouhal numbers are reported from cavitation-free flow (classic von Karman vortex shedding) up to supercavitation as a function of the free-stream Reynolds number. The results are in good agreement with the literature in case of the square cylinder. We experienced a slight increase of the dominant Strouhal number with increasing aspect ratio. This result is somewhat inconsistent with the literature, in which a fall of the Strouhal number can be observed at side ratio 2. This may be the consequence of the different ranges of Reynolds numbers. It was also found that between the inception of cavitation and the formation of supercavitation the Strouhal number is not affected by cavitation.

  1. Effect of flow rate distribution at the inlet on hydrodynamic mixing in narrow rectangular multi-channel

    International Nuclear Information System (INIS)

    Xu Jianjun; Chen Bingde; Wang Xiaojun

    2008-01-01

    Flow and heat transfer in the narrow rectangular multi-channel is widely en- countered in the engineering application, hydrodynamic mixing in the narrow rectangular multi-channel is one of the important concerns. With the help of the Computational Fluid Dynamics code CFX, the effect of flow rate distribution of the main channel at the inlet on hydrodynamic mixing in the narrow rectangular multi-channel is numerical simulated. The results show that the flow rate distributions at the inlet have a great effect on hydrodynamics mixing in multi-channel, the flow rate in the main channel doesn't change with increasing the axial mixing section when the average flow rate at the inlet is set. Hydrodynamic mixing will arise in the mixing section when the different ratio of the flow rate distribution at the inlet is set, and hydrodynamic mixing increases with the difference of the flow rate distribution at the inlet increase. The trend of the flow rate distribution of the main channel is consistent during the whole axial mixing section, and hydrodynamic mixing in former 4 mixing section is obvious. (authors)

  2. Create Your Plate

    Medline Plus

    Full Text Available ... Plate Share Create Your Plate ! Share: Seven Simple Steps to Create Your Plate It's simple and effective ... foods within each food category. Try these seven steps to get started: Using your dinner plate, put ...

  3. SPH modeling of fluid-solid interaction for dynamic failure analysis of fluid-filled thin shells

    Science.gov (United States)

    Caleyron, F.; Combescure, A.; Faucher, V.; Potapov, S.

    2013-05-01

    This work concerns the prediction of failure of a fluid-filled tank under impact loading, including the resulting fluid leakage. A water-filled steel cylinder associated with a piston is impacted by a mass falling at a prescribed velocity. The cylinder is closed at its base by an aluminum plate whose characteristics are allowed to vary. The impact on the piston creates a pressure wave in the fluid which is responsible for the deformation of the plate and, possibly, the propagation of cracks. The structural part of the problem is modeled using Mindlin-Reissner finite elements (FE) and Smoothed Particle Hydrodynamics (SPH) shells. The modeling of the fluid is also based on an SPH formulation. The problem involves significant fluid-structure interactions (FSI) which are handled through a master-slave-based method and the pinballs method. Numerical results are compared to experimental data.

  4. Effect of the configuration of the corner in a narrow rectangular channel on flow and heat transfer

    International Nuclear Information System (INIS)

    Xu Jianjun; Chen Bingde; Wang Xiaojun

    2009-01-01

    In order to further understand the effect of the configuration of the corner in a narrow rectangular channel on flow and heat transfer, flow field and temperature field in a narrow rectangular channel were numerical simulated by using CFD code CFX10.0. The results show under the condition of equal quantity of heat of solid which is obtained by decreasing the solid of the corner, the distributions of inside wall temperature for the orthogonal and circular type configurations of the corner are almost the same as that of the archetypal configuration, and those can simulate heat transfer of the archetypal con- figuration. Under the condition of equal Re, secondary flow and friction pressure of the orthogonal type configuration are almost the same as those of the circular type configuration, which shows that the circular type configuration of the corner in a narrow channel can substituted for the archetypal configuration to simulate flow and heat transfer in a narrow rectangular channel. (authors)

  5. Treatment of mandibular angle fracture with a 2mm, 3 dimensional rectangular grid compression miniplates: A prospective clinical study.

    Science.gov (United States)

    Mansuri, Samir; Abdulkhayum, Abdul Mujeeb; Gazal, Giath; Hussain, Mohammed Abid Zahir

    2013-12-01

    Surgical treatment of fracture mandible using an internal fixation has changed in the last decades to achieve the required rigidity, stability and immediate restoration of function. The aim of the study was to do a Prospective study of 10 patients to determine the efficacy of rectangular grid compression miniplates in mandibular fractures. This study was carried out using 2.0 rectangular grid compression miniplates and 8 mm multidirectional screws as a rigid internal fixation in 10 patients without post operative intermaxillary fixation (IMF). Follow up was done for period of 6 months. All fractures were healed with an absolute stability in post operative period. None of the patient complained of post operative difficulty in occlusion. Within the limits of this study, it can be concluded that rectangular grid compression miniplates was rigid, reliable and thus can be recommended for the treatment of mandibular angle fractures. How to cite this article: Mansuri S, Abdulkhayum AM, Gazal G, Hussain MA. Treatment of mandibular angle fracture with a 2mm, 3 dimensional rectangular grid compression miniplates: A prospective clinical study. J Int Oral Health 2013;5(6):93-100 .

  6. Inertial manipulation of bubbles in rectangular microfluidic channels.

    Science.gov (United States)

    Hadikhani, Pooria; Hashemi, S Mohammad H; Balestra, Gioele; Zhu, Lailai; Modestino, Miguel A; Gallaire, François; Psaltis, Demetri

    2018-03-27

    Inertial microfluidics is an active field of research that deals with crossflow positioning of the suspended entities in microflows. Until now, the majority of the studies have focused on the behavior of rigid particles in order to provide guidelines for microfluidic applications such as sorting and filtering. Deformable entities such as bubbles and droplets are considered in fewer studies despite their importance in multiphase microflows. In this paper, we show that the trajectory of bubbles flowing in rectangular and square microchannels can be controlled by tuning the balance of forces acting on them. A T-junction geometry is employed to introduce bubbles into a microchannel and analyze their lateral equilibrium position in a range of Reynolds (1 < Re < 40) and capillary numbers (0.1 < Ca < 1). We find that the Reynolds number (Re), the capillary number (Ca), the diameter of the bubble (D[combining macron]), and the aspect ratio of the channel are the influential parameters in this phenomenon. For instance, at high Re, the flow pushes the bubble towards the wall while large Ca or D[combining macron] moves the bubble towards the center. Moreover, in the shallow channels, having aspect ratios higher than one, the bubble moves towards the narrower sidewalls. One important outcome of this study is that the equilibrium position of bubbles in rectangular channels is different from that of solid particles. The experimental observations are in good agreement with the performed numerical simulations and provide insights into the dynamics of bubbles in laminar flows which can be utilized in the design of flow based multiphase flow reactors.

  7. Influence of old rectangular repair patches on the burst pressure of a gas pipeline

    International Nuclear Information System (INIS)

    Fazzini, Pablo Gabriel; Otegui, Jose Luis

    2006-01-01

    Seven full scale hydrostatic burst tests were carried out on pipes extracted from an API 5LX52 gas pipeline that contained rectangular and elliptical fillet welded patches and other repairs of different geometries. All breaks took place after widespread yielding. This analysis shows that the patches that generate greater risks are those that: (1) were attached to the pipeline at very low pressure (2) were placed to repair large defects (3) are rectangular, long in the direction of the pipe, and narrow (4) the quality of the weld is doubtful. Based on data reported by In Line Inspection (ILI), of the four conditions mentioned above, only the third can be assessed in order to quantify risks and to schedule replacements

  8. Large - scale Rectangular Ruler Automated Verification Device

    Science.gov (United States)

    Chen, Hao; Chang, Luping; Xing, Minjian; Xie, Xie

    2018-03-01

    This paper introduces a large-scale rectangular ruler automated verification device, which consists of photoelectric autocollimator and self-designed mechanical drive car and data automatic acquisition system. The design of mechanical structure part of the device refer to optical axis design, drive part, fixture device and wheel design. The design of control system of the device refer to hardware design and software design, and the hardware mainly uses singlechip system, and the software design is the process of the photoelectric autocollimator and the automatic data acquisition process. This devices can automated achieve vertical measurement data. The reliability of the device is verified by experimental comparison. The conclusion meets the requirement of the right angle test procedure.

  9. Design of open rectangular and trapezoidal channels

    Science.gov (United States)

    González, C. P.; Vera, P. E.; Carrillo, G.; García, S.

    2018-04-01

    In this work, the results of designing open channels in rectangular and trapezoidal form are presented. For the development of the same important aspects were taken as determination of flows by means of formula of the rational method, area of the surface for its implementation, optimal form of the flow to meet the needs of that environment. In the design the parameter of the hydraulic radius expressed in terms of the hydraulic area and wet perimeter was determined, considering that the surface on which the fluid flows is the product of the perimeter of the section and the length of the channel and where shear is generated by the condition of no slippage.

  10. Torque efficiency of square and rectangular archwires into 0.018 and 0.022 in. conventional brackets.

    Science.gov (United States)

    Papageorgiou, Spyridon N; Sifakakis, Iosif; Doulis, Ioannis; Eliades, Theodore; Bourauel, Christoph

    2016-01-01

    The aim of this study was to compare the torque efficacy of square and rectangular wires in 0.018- and 0.022-in. conventionally ligated brackets. Brackets of the same prescription were evaluated in both slot dimensions. Identical acrylic resin models of the maxilla were bonded with the brackets and mounted on the Orthodontic Measurement and Simulation System. Ten 0.018 × 0.018 in., 0.018 × 0.022 in., and 0.018 × 0.025 in. stainless steel wires were evaluated in the 0.018-in. brackets and ten 0.019 × 0.019 in., 0.019 × 0.025 in., and 0.019 × 0.026 in. stainless steel wires were evaluated in the 0.022-in. brackets. A 15° buccal root torque was gradually applied to the right central incisor bracket, and the moments were recorded at this position. One-way ANOVA was applied for both bracket slot sizes along with post hoc analysis for the various archwire sizes. The mean measured moments varied between 10.78 and 30.60 Nmm among the assessed wire-and-bracket combinations. Both square and rectangular archwires in the 0.018-in. bracket system exerted statistically significantly higher moments in comparison with their counterparts in the 0.022-in. bracket system. Rectangular archwires exerted statistically significantly higher moments than square archwires, both for the 0.018- and the 0.022-in. bracket system. Rectangular archwires seem to be more efficient in torque exertion, especially in 0.018-in. brackets.

  11. MHD and heat transfer benchmark problems for liquid metal flow in rectangular ducts

    International Nuclear Information System (INIS)

    Sidorenkov, S.I.; Hua, T.Q.; Araseki, H.

    1994-01-01

    Liquid metal cooling systems of a self-cooled blanket in a tokamak reactor will likely include channels of rectangular cross section where liquid metal is circulated in the presence of strong magnetic fields. MHD pressure drop, velocity distribution and heat transfer characteristics are important issues in the engineering design considerations. Computer codes for the reliable solution of three-dimensional MHD flow problems are needed for fusion relevant conditions. Argonne National Laboratory and The Efremov Institute have jointly defined several benchmark problems for code validation. The problems, described in this paper, are based on two series of rectangular duct experiments conducted at ANL; one of the series is a joint ANL/Efremov experiment. The geometries consist of variation of aspect ratio and wall thickness (thus wall conductance ratio). The transverse magnetic fields are uniform and nonuniform in the axial direction

  12. Development of Metal Plate with Internal Structure Utilizing the Metal Injection Molding (MIM Process

    Directory of Open Access Journals (Sweden)

    Kwangho Shin

    2013-12-01

    Full Text Available In this study, we focus on making a double-sided metal plate with an internal structure, such as honeycomb. The stainless steel powder was used in the metal injection molding (MIM process. The preliminary studies were carried out for the measurement of the viscosity of the stainless steel feedstock and for the prediction of the filling behavior through Computer Aided Engineering (CAE simulation. PE (high density polyethylene (HDPE and low density polyethylene (LDPE and polypropylene (PP resins were used to make the sacrificed insert with a honeycomb structure using a plastic injection molding process. Additionally, these sacrificed insert parts were inserted in the metal injection mold, and the metal injection molding process was carried out to build a green part with rectangular shape. Subsequently, debinding and sintering processes were adopted to remove the sacrificed polymer insert. The insert had a suitable rigidity that was able to endure the filling pressure. The core shift analysis was conducted to predict the deformation of the insert part. The 17-4PH feedstock with a low melting temperature was applied. The glass transition temperature of the sacrificed polymer insert would be of a high grade, and this insert should be maintained during the MIM process. Through these processes, a square metal plate with a honeycomb structure was made.

  13. Heat transfer augmentation in rectangular micro channel covered with vertically aligned carbon nanotubes

    NARCIS (Netherlands)

    Taha, T.J.; Lefferts, Leonardus; van der Meer, Theodorus H.

    2016-01-01

    An experimental heat transfer investigation was carried out to examine the influence of carbon nanotubes (CNTs) layer deposits on the convective heat transfer performance inside rectangular microchannels. Successful synthesis of vertically aligned CNTs was achieved using a catalytic vapor deposition

  14. Paper microzone plates.

    Science.gov (United States)

    Carrilho, Emanuel; Phillips, Scott T; Vella, Sarah J; Martinez, Andres W; Whitesides, George M

    2009-08-01

    This paper describes 96- and 384-microzone plates fabricated in paper as alternatives to conventional multiwell plates fabricated in molded polymers. Paper-based plates are functionally related to plastic well plates, but they offer new capabilities. For example, paper-microzone plates are thin (approximately 180 microm), require small volumes of sample (5 microL per zone), and can be manufactured from inexpensive materials ($0.05 per plate). The paper-based plates are fabricated by patterning sheets of paper, using photolithography, into hydrophilic zones surrounded by hydrophobic polymeric barriers. This photolithography used an inexpensive formulation photoresist that allows rapid (approximately 15 min) prototyping of paper-based plates. These plates are compatible with conventional microplate readers for quantitative absorbance and fluorescence measurements. The limit of detection per zone loaded for fluorescence was 125 fmol for fluorescein isothiocyanate-labeled bovine serum albumin, and this level corresponds to 0.02 the quantity of analyte per well used to achieve comparable signal-to-noise in a 96-well plastic plate (using a solution of 25 nM labeled protein). The limits of detection for absorbance on paper was approximately 50 pmol per zone for both Coomassie Brilliant Blue and Amaranth dyes; these values were 0.4 that required for the plastic plate. Demonstration of quantitative colorimetric correlations using a scanner or camera to image the zones and to measure the intensity of color, makes it possible to conduct assays without a microplate reader.

  15. Premature and stable critical heat flux for downward flow in a narrow rectangular channel

    International Nuclear Information System (INIS)

    Lee, Juhyung; Chang, Soon Heung; Jeong, Yong Hoon; Jo, Daeseong

    2014-01-01

    It has been recommended that RRs and MTRs be designed to have sufficient margins for CHF and the onset of FI as well, since unstable flow could leads to premature CHF under very low wall heat flux in comparison to stable CHF. Even the fact and previous studies, however, the understanding of relationship among FI, premature CHF and stable CHF is not sufficient to date. In this regards, subcooled flow boiling in a vertical rectangular channel was experimentally investigated to enhance the understanding of the CHF and the effect of the two-phase flow instability on it under low pressure conditions, especially for downward flow which was adopted for Jordan Research and Training Reactor (JRTR) and Kijang research reactor (KJRR) to achieve easier fuel and irradiation rig loading. In this study, CHF for downward flow of water under low pressure in narrow rectangular channel was experimentally investigated. For conditions such as downward flow, narrow rectangular channel and low pressure, it has been deduced from literature that flow instability could largely influence on triggering CHF at lower heat flux, i. e. premature CHF. Total 54 CHF data, which includes premature and stable data was obtained for various fluid conditions and system configurations including inlet stiffness. The upper and lower boundaries of CHF were newly proposed based on the experiment

  16. Experimental verification of the axial and lateral stiffness of large W7-X rectangular bellows

    International Nuclear Information System (INIS)

    Reich, J.; Cardella, A.; Koppe, T.; Missal, B.; Capriccioli, A.; Loehrer, W.; Langone, S.; Sassone, P.C.

    2006-01-01

    The WENDELSTEIN 7-X (W7-X) is a super-conducting helical advanced stellarator. W7-X is provided with 299 ports, which connect the plasma vessel with the outer vessel. All the ports are equipped with bellows, which, during bake-out and final adjustment, compensate the relative movements of the vessels. The bellows have different shapes and dimensions ranging from 100 mm circular to 1170 x 570 mm rectangular sizes. During various load-cases the axial and lateral stiffness of all bellows will create a resulting spring-force which acts on the supports of the vessels directly. The higher the stiffness the more is the significant influence on the supports. The lateral stiffness which was calculated with the established standard EJMA-code (Expansion Joint Manufacturers Association) seemed to be relatively small. This appeared to be not correct in particular for non circular bellows. That is why the stiffness of rectangular, multi-layer bellows have then been re-calculated with the Finite Element Method (FEM) code ANSYS. The maximum difference between the FEM and EJMA code resulted to be up to 250 % in particular with movements along the longer side of the bellows. In order to clarify the differences a test-campaign with the largest rectangular bellows was performed. A special test rack allowed predefined displacements in pure lateral and axial directions taking into consideration of the friction in the moving elements. During the tests the load-displacement diagram was recorded permanently. The outcome of the FEM-results was then verified by the tests in axial and lateral directions. The EJMA-code is well proved for circular bellows. The tests showed that instead any calculation of rectangular bellows has to be confirmed by experiments. The paper summarises the calculation, describes the test activities, the apparatus and reports the final results. (author)

  17. On Stability of Exact Transparent Boundary Condition for the Parabolic Equation in Rectangular Computational Domain

    Science.gov (United States)

    Feshchenko, R. M.

    Recently a new exact transparent boundary condition (TBC) for the 3D parabolic wave equation (PWE) in rectangular computational domain was derived. However in the obtained form it does not appear to be unconditionally stable when used with, for instance, the Crank-Nicolson finite-difference scheme. In this paper two new formulations of the TBC for the 3D PWE in rectangular computational domain are reported, which are likely to be unconditionally stable. They are based on an unconditionally stable fully discrete TBC for the Crank-Nicolson scheme for the 2D PWE. These new forms of the TBC can be used for numerical solution of the 3D PWE when a higher precision is required.

  18. Slug-annular transition with particular reference to narrow rectangular ducts

    International Nuclear Information System (INIS)

    Jones, O.C. Jr.; Zuber, N.

    1978-01-01

    The transition from slug-flow to annular-flow in two-phase, gas-liquid mixtures is analyzed. A transition equation is derived which agrees well when compared with objective data determined from the disappearance of the low-void peak in the void fluctuation probability density in a rectangular duct. Application to other geometries is suggested and tabular recommendations given for determination of the drift flux coefficient, K, based on results in the literature

  19. Buoyancy effects in vertical rectangular duct with coplanar magnetic field and single sided heat load

    Science.gov (United States)

    Kostichev, P. I.; Poddubnyi, I. I.; Razuvanov, N. G.

    2017-11-01

    In some DEMO blanket designs liquid metal flows in vertical ducts of rectangular cross-section between ceramic breeder units providing their cooling. Heat exchange in these conditions is governed by the influence of magnetic field (coplanar) and by buoyancy effects that depend on the flow orientation to the gravity vector (downward and upward flow). Magnetohydrodynamic and heat transfer of liquid metal in vertical rectangular ducts is not well researched. Experimental study of buoyancy effects in rectangular duct with coplanar magnetic field for one-sided heat load and downward and upward flowsis presented in this paper. The detail research with has been done on mercury MHD close loop with using of the probe technique allow to discover several advantageous and disadvantageous effects. The intensive impact of buoyancy force has been observed in a few regime of downward flow which has been laminarized by magnetic field. Due to the development in the flow of the secondary large-scale vortices heat transfer improved and the temperature fluctuations of the abnormally high intensity have been fixed. On the contrary, in the upward flow the buoyancy force stabilized the flow which lead to decreasing of the turbulence heat transfer ratio and, consequently, deterioration of heat transfer.

  20. Tabu Search-based Synthesis of Digital Microfluidic Biochips with Dynamically Reconfigurable Non-rectangular Devices

    DEFF Research Database (Denmark)

    Maftei, Elena; Pop, Paul; Madsen, Jan

    2010-01-01

    they are highly reconfigurable and scalable. A digital biochip is composed of a two-dimensional array of cells, together with reservoirs for storing the samples and reagents. Several adjacent cells are dynamically grouped to form a virtual device, on which operations are performed. So far, researchers have...... assumed that throughout its execution, an operation is performed on a rectangular virtual device, whose position remains fixed. However, during the execution of an operation, the virtual device can be reconfigured to occupy a different group of cells on the array, forming any shape, not necessarily...... rectangular. In this paper, we present a Tabu Search metaheuristic for the synthesis of digital microfluidic biochips, which, starting from a biochemical application and a given biochip architecture, determines the allocation, resource binding, scheduling and placement of the operations in the application...

  1. Gamma radiation inside closed volumes with thin irradiating walls

    International Nuclear Information System (INIS)

    Karpov, V.I.

    1978-01-01

    The dose rate of gamma radiation inside a parallelepiped with thin radiating walls was calculated. The calculation was based on determining the dose rate from a rectangular plate and subsequently summing the dose rates from all the parallelepiped walls. The dose rate from the rectangular plate was calculated by reducing it to an equivalent plate of infinite length and certain fixed width. When the radiators had constant surface density, the dose rate in the geometric centre of volumes having the form of a parallelepiped was shown to have the least value in the case when the parallelepiped degenerates to a cube

  2. Realization of Rectangular Artificial Spin Ice and Direct Observation of High Energy Topology.

    Science.gov (United States)

    Ribeiro, I R B; Nascimento, F S; Ferreira, S O; Moura-Melo, W A; Costa, C A R; Borme, J; Freitas, P P; Wysin, G M; de Araujo, C I L; Pereira, A R

    2017-10-25

    In this work, we have constructed and experimentally investigated frustrated arrays of dipoles forming two-dimensional artificial spin ices with different lattice parameters (rectangular arrays with horizontal and vertical lattice spacings denoted by a and b respectively). Arrays with three different aspect ratios γ = a/b = [Formula: see text], [Formula: see text] and [Formula: see text] are studied. Theoretical calculations of low-energy demagnetized configurations for these same parameters are also presented. Experimental data for demagnetized samples confirm most of the theoretical results. However, the highest energy topology (doubly-charged monopoles) does not emerge in our theoretical model, while they are seen in experiments for large enough γ. Our results also insinuate that the string tension connecting two magnetic monopoles in a pair vanishes in rectangular lattices with a critical ratio γ = γ c  = [Formula: see text], supporting previous theoretical predictions.

  3. Coupling Poisson rectangular pulse and multiplicative microcanonical random cascade models to generate sub-daily precipitation timeseries

    Science.gov (United States)

    Pohle, Ina; Niebisch, Michael; Müller, Hannes; Schümberg, Sabine; Zha, Tingting; Maurer, Thomas; Hinz, Christoph

    2018-07-01

    To simulate the impacts of within-storm rainfall variabilities on fast hydrological processes, long precipitation time series with high temporal resolution are required. Due to limited availability of observed data such time series are typically obtained from stochastic models. However, most existing rainfall models are limited in their ability to conserve rainfall event statistics which are relevant for hydrological processes. Poisson rectangular pulse models are widely applied to generate long time series of alternating precipitation events durations and mean intensities as well as interstorm period durations. Multiplicative microcanonical random cascade (MRC) models are used to disaggregate precipitation time series from coarse to fine temporal resolution. To overcome the inconsistencies between the temporal structure of the Poisson rectangular pulse model and the MRC model, we developed a new coupling approach by introducing two modifications to the MRC model. These modifications comprise (a) a modified cascade model ("constrained cascade") which preserves the event durations generated by the Poisson rectangular model by constraining the first and last interval of a precipitation event to contain precipitation and (b) continuous sigmoid functions of the multiplicative weights to consider the scale-dependency in the disaggregation of precipitation events of different durations. The constrained cascade model was evaluated in its ability to disaggregate observed precipitation events in comparison to existing MRC models. For that, we used a 20-year record of hourly precipitation at six stations across Germany. The constrained cascade model showed a pronounced better agreement with the observed data in terms of both the temporal pattern of the precipitation time series (e.g. the dry and wet spell durations and autocorrelations) and event characteristics (e.g. intra-event intermittency and intensity fluctuation within events). The constrained cascade model also

  4. The demagnetizing factors for the rectangular samples

    International Nuclear Information System (INIS)

    Akishin, P.G.; Gaganov, I.A.

    1990-01-01

    The influence of the demagnetization effect on the distribution of internal magnetic fields for finite samples is considered. The boundary integral method is used to compute the space distribution of the magnetic field in rectangular samples. On the basis of these calculations we compute the distribution of demagnetization factors in the sample for μSR experimental set-up with the real field geometry. The corresponding mathematical expectation and dispersion of this distribution are estimated. The results of the calculation are used in the analysis of the μSR data obtained for high T c superconductors. It is shown for these compounds that the correction to the penetration depth related to the broadening of the field distribution, is not more than 5%. 8 refs.; 2 figs.; 1 tab

  5. Experimental study of falling film evaporation in large scale rectangular channel

    International Nuclear Information System (INIS)

    Huang, X.G.; Yang, Y.H.; Hu, P.

    2015-01-01

    Highlights: • This paper studies the falling film evaporation in large scale rectangular channel experimentally. • The effects of air flow rate, film temperature and film flow rate on falling film evaporation are analyzed. • Increasing the air flow rate is considered as an efficient method to enhance the evaporation rate. • A correlation including the wave effect for falling film evaporation is derived based on heat and mass transfer analogy. - Abstract: The falling film evaporation in a large scale rectangular channel is experimentally studied in this paper for the design and improvement of passive containment cooling system. The evaporation mass transfer coefficient h D is obtained by the evaporation rate and vapor partial pressure difference of film surface and air bulk. The experimental results indicate that increasing of air flow rate appears to enhance h D , while the film temperature and film flow rate have little effect on h D . Since the wave effect on evaporation is noticed in experiment, the evaporation mass transfer correlation including the wave effect is developed on the basis of heat and mass transfer analogy and experimental data

  6. Experimental Investigation of Thermohydraulic Performance of a Rectangular Solar Air Heater Duct Equipped with V-Shaped Perforated Blocks

    Directory of Open Access Journals (Sweden)

    Tabish Alam

    2014-01-01

    Full Text Available This paper presents the thermohydraulic performance of rectangular solar air heater duct equipped with V-shaped rectangular perforated blocks attached to the heated surface. The V-shaped perforated blocks are tested for downstream (V-down to the air flow at Reynolds number from 2000 to 20000. The perforated blocks have relative pitch ratio (P/e from 4 to 12, relative blockage height ratio (e/H from 0.4 to 1.0, and open area ration from 5% to 25% at a fixed value of angle of attack of 60∘ in a rectangular duct having duct aspect ratio (W/H of 12. Thermohydraulic performance is compared at different geometrical parameters of V-shaped perforated blocks for equal pumping power which shows that maximum performance is observed at a relative pitch of 8, relative rib height of 0.8, and open area ration of 20%. It is also observed that the performance of V-shaped perforated blocks was better than transverse-perforated blocks.

  7. Locking screw-plate interface stability in carbon-fibre reinforced polyetheretherketone proximal humerus plates.

    Science.gov (United States)

    Hak, David J; Fader, Ryan; Baldini, Todd; Chadayammuri, Vivek B S

    2017-09-01

    Carbon-fibre reinforced polyetheretherketone (CFR-PEEK) plates have recently been introduced for proximal humerus fracture treatment. The purpose of this study was to compare the locking screw-plate interface stability in CFR-PEEK versus stainless steel (SS) proximal humerus plates. Locking screw mechanical stability was evaluated independently in proximal and shaft plate holes. Stiffness and load to failure were tested for three conditions: (1) on-axis locking screw insertion in CFR-PEEK versus SS plates, (2) on-axis locking screw insertion, removal, and reinsertion in CFR-PEEK plates, and (3) 10-degree off-axis locking screw insertion in CFR-PEEK plates. Cantilever bending at a rate of 1 mm/minute was produced by an Instron machine and load-displacement data recorded. Shaft locking screw load to failure was significantly greater in CFR-PEEK plates compared to SS plates (746.4 ± 89.7 N versus 596.5 ± 32.6 N, p PEEK plates (p PEEK plates. The mechanical stability of locking screws in CFR-PEEK plates is comparable or superior to locking screws in SS plates.

  8. Analysis of some coplanar transmission lines: coplanar coupled lines, coplanar coupled striplines, and coplanar coupled lines with rectangular microshield

    Science.gov (United States)

    Yuan, Naichang; He, Jianguo; Yao, Demiao; Dai, Qin; Lin, Weigan

    1995-06-01

    Two types of coplanar transmission lines, rectangular microshield coplanar coupled lines (RMCCL) and coplanar coupled rectangular microshield lines (CCRML), are proposed for MMIC applications. These are developed from coplanar coupled lines (CCL) and coplanar coupled strip lines (CCS). Analytic formulas are presented for calculating the quasistatic TEM parameters of these coupled lines by means of exact conformal mapping techniques. Numerical results are also presented to illustrate the properties of these coplanar transmission lines.

  9. On improvement of the series convergence in the problem of the vibrations of orhotropic rectangular prism

    Science.gov (United States)

    Lyashko, A. D.

    2017-11-01

    A new analytical presentation of the solution for steady-state oscillations of orthotopic rectangular prism is found. The corresponding infinite system of linear algebraic equations has been deduced by the superposition method. A countable set of precise eigenfrequencies and elementary eigenforms is found. The identities are found which make it possible to improve the convergence of all the infinite series in the solution of the problem. All the infinite series in presentation of solution are analytically summed up. Numerical calculations of stresses in the rectangular orthotropic prism with a uniform along the border and harmonic in time load on two opposite faces have been performed.

  10. Edge Effects in a Composite Weakly Reinforced with Fibers of Rectangular Cross Section

    Science.gov (United States)

    Boichuk, V. Yu.

    2001-05-01

    This paper deal with the edge effect in a composite weakly reinforced with fibers of rectangular cross section and subjected to biaxial uniform loading. The edge effects due to the difference between Poisson's ratios of the composite components are studied. Numerical results are presented

  11. Voltage-current characteristics of a pin-plate system with different plate configurations

    International Nuclear Information System (INIS)

    Feng, Zhuangbo; Long, Zhengwei

    2013-01-01

    In this paper, the voltage-current (V-I) characteristics of a pin-plate system with four types of collection plate configurations are studied experimentally. The collection plates consider a single metal plate, a metal plate with a fly ash cake layer, a metal plate with a clean filter media and a metal plate with a dirty filter media. The results show that the clean filter media has no obvious effect on the V-I characteristics. But the dirty filter media reduces the current density because of its high resistance. The thick fly ash cake layer increase current density because of the anti-corona effect but the increment is not very obvious.

  12. The demagnetizing field of a non-uniform rectangular prism

    DEFF Research Database (Denmark)

    Smith, Anders; Nielsen, Kaspar Kirstein; Christensen, Dennis

    2010-01-01

    The effect of demagnetization on the magnetic properties of a rectangular ferromagnetic prism under non-uniform conditions is investigated. A numerical model for solving the spatially varying internal magnetic field is developed, validated and applied to relevant cases. The demagnetizing field...... is solved by an analytical calculation and the coupling between applied field, the demagnetization tensor field and spatially varying temperature is solved through iteration. We show that the demagnetizing field is of great importance in many cases and that it is necessary to take into account the non...

  13. Regimes of Two-Phase Flow in Short Rectangular Channel

    Science.gov (United States)

    Chinnov, Evgeny A.; Guzanov, Vladimir V.; Cheverda, Vyacheslav; Markovich, Dmitry M.; Kabov, Oleg A.

    2009-08-01

    Experimental study of two-phase flow in the short rectangular horizontal channel with height 440 μm has been performed. Characteristics of liquid motion inside the channel have been registered and measured by the Laser Induced Fluorescence technique. New information has allowed determining more precisely the characteristics of churn regime and boundaries between different regimes of two-phase flow. It was shown that formation of some two-phase flow regimes and transitions between them are determined by instability of the flow in the lateral parts of the channel.

  14. Numerical and Experimental Analysis on the Cavity Formation and Shrinkage for Investment Cast Alloy 738 4 mm-Thick Rectangular Tube

    International Nuclear Information System (INIS)

    Park, Myeong-Il; Choi, Yoon Suk; Yoo, Jae-Hyun; Park, Sang-Hu; Kim, Kyeong-Min; Lee, Yeong-Chul; Lee, Jung-Seok; Lee, Jae-Hyun

    2017-01-01

    Investment casting for the thin (4 mm thick) rectangular tube (40 mm wide, 80 mm high and 200 mm long) was carried out numerically and experimentally for Alloy 738, which is a precipitation-hardened Ni-base superalloy. Two types of rectangular tubes, one with a regular array (10 mm by 10 mm square array) of protruded rods (3 mm in diameter and 3mm in height) embedded on the outer surface and the other with just smooth surface, were investment-cast at the same time through the side feeding mold design. The investment casting simulation predicted the presence of cavities, particularly in the area away from the gate for both types of rectangular tubes. In particular, for the rectangular tube with embedded protruded rods cavities were found mainly in the areas between the protruded rods. This simulation result was qualitatively consistent with the experimental observation from the X-ray analysis. Also, both prediction and experiment showed that the dimensional shrinkage (particularly in the longitudinal direction) of the investment-cast rectangular tube is reduced by having protruded rods embedded on the outer surface. Additional numerical attempts were made to check how the amount of cavities and dimensional shrinkage change by varying the preheating temperature and the thickness of the mold. The results predicted that the amount of cavities and the dimensional shrinkage are significantly reduced by increasing the preheating temperature of the mold by 200 ℃. However, an increase in mold thickness from 10 mm to 12 mm showed almost no difference in cavity population and a slight decrease in dimensional shrinkage.

  15. Numerical and Experimental Analysis on the Cavity Formation and Shrinkage for Investment Cast Alloy 738 4 mm-Thick Rectangular Tube

    Energy Technology Data Exchange (ETDEWEB)

    Park, Myeong-Il; Choi, Yoon Suk; Yoo, Jae-Hyun; Park, Sang-Hu [Pusan National University, Busan (Korea, Republic of); Kim, Kyeong-Min; Lee, Yeong-Chul [Sung Il Turbine Co., Ltd., Busan (Korea, Republic of); Lee, Jung-Seok; Lee, Jae-Hyun [Changwon National University, Changwon (Korea, Republic of)

    2017-02-15

    Investment casting for the thin (4 mm thick) rectangular tube (40 mm wide, 80 mm high and 200 mm long) was carried out numerically and experimentally for Alloy 738, which is a precipitation-hardened Ni-base superalloy. Two types of rectangular tubes, one with a regular array (10 mm by 10 mm square array) of protruded rods (3 mm in diameter and 3mm in height) embedded on the outer surface and the other with just smooth surface, were investment-cast at the same time through the side feeding mold design. The investment casting simulation predicted the presence of cavities, particularly in the area away from the gate for both types of rectangular tubes. In particular, for the rectangular tube with embedded protruded rods cavities were found mainly in the areas between the protruded rods. This simulation result was qualitatively consistent with the experimental observation from the X-ray analysis. Also, both prediction and experiment showed that the dimensional shrinkage (particularly in the longitudinal direction) of the investment-cast rectangular tube is reduced by having protruded rods embedded on the outer surface. Additional numerical attempts were made to check how the amount of cavities and dimensional shrinkage change by varying the preheating temperature and the thickness of the mold. The results predicted that the amount of cavities and the dimensional shrinkage are significantly reduced by increasing the preheating temperature of the mold by 200 ℃. However, an increase in mold thickness from 10 mm to 12 mm showed almost no difference in cavity population and a slight decrease in dimensional shrinkage.

  16. Simulation of natural convection in a rectangular loop using finite elements

    International Nuclear Information System (INIS)

    Pepper, D.W.; Hamm, L.L.; Kehoe, A.B.

    1984-01-01

    A two-dimensional finite-element analysis of natural convection in a rectangular loop is presented. A psi-omega formulation of the Boussinesque approximation to the Navier-Stokes equation is solved by the false transient technique. Streamlines and isotherms at Ra = 10 4 are shown for three different modes of heating. The results indicate that corner effects should be considered when modeling flow patterns in thermosyphons

  17. Transmission line model for coupled rectangular double split‐ring resonators

    DEFF Research Database (Denmark)

    Yan, Lei; Tang, Meng; Krozer, Viktor

    2011-01-01

    In this work, a model based on a coupled transmission line formulation is developed for microstrip rectangular double split‐ring resonators (DSRRs). This model allows using the physical dimensions of the DSRRs as an input avoiding commonly used extraction of equivalent parameters. The model inclu...... simulations of the DSRR structures. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:1311–1315, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25988...

  18. Springback Mechanism Analysis and Experiments on Robotic Bending of Rectangular Orthodontic Archwire

    Science.gov (United States)

    Jiang, Jin-Gang; Han, Ying-Shuai; Zhang, Yong-De; Liu, Yan-Jv; Wang, Zhao; Liu, Yi

    2017-11-01

    Fixed-appliance technology is the most common and effective malocclusion orthodontic treatment method, and its key step is the bending of orthodontic archwire. The springback of archwire did not consider the movement of the stress-strain-neutral layer. To solve this problem, a springback calculation model for rectangular orthodontic archwire is proposed. A bending springback experiment is conducted using an orthodontic archwire bending springback measurement device. The springback experimental results show that the theoretical calculation results using the proposed model coincide better with the experimental testing results than when movement of the stress-strain-neutral layer was not considered. A bending experiment with rectangular orthodontic archwire is conducted using a robotic orthodontic archwire bending system. The patient expriment result show that the maximum and minimum error ratios of formed orthodontic archwire parameters are 22.46% and 10.23% without considering springback and are decreased to 11.35% and 6.13% using the proposed model. The proposed springback calculation model, which considers the movement of the stress-strain-neutral layer, greatly improves the orthodontic archwire bending precision.

  19. Magnetohydrodynamic flow of generalized Maxwell fluids in a rectangular micropump under an AC electric field

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Guangpu [School of Mathematical Science, Inner Mongolia University, Hohhot, Inner Mongolia 010021 (China); Jian, Yongjun, E-mail: jianyj@imu.edu.cn [School of Mathematical Science, Inner Mongolia University, Hohhot, Inner Mongolia 010021 (China); Chang, Long [School of Mathematics and Statistics, Inner Mongolia University of Finance and Economics, Hohhot, Inner Mongolia 010051 (China); Buren, Mandula [School of Mathematical Science, Inner Mongolia University, Hohhot, Inner Mongolia 010021 (China)

    2015-08-01

    By using the method of separation of variables, an analytical solution for the magnetohydrodynamic (MHD) flow of the generalized Maxwell fluids under AC electric field through a two-dimensional rectangular micropump is reduced. By the numerical computation, the variations of velocity profiles with the electrical oscillating Reynolds number Re, the Hartmann number Ha, the dimensionless relaxation time De are studied graphically. Further, the comparison with available experimental data and relevant researches is presented. - Highlights: • MHD flow of the generalized Maxwell fluids under AC electric field is analyzed. • The MHD flow is confined to a two-dimensional rectangular micropump. • Analytical solution is obtained by using the method of separation of variables. • The influences of related parameters on the MHD velocity are discussed.

  20. Aeroacoustics of rectangular T-junctions subject to combined grazing and bias flows - An experimental investigation

    Science.gov (United States)

    Holmberg, Andreas; Karlsson, Mikael; Åbom, Mats

    2015-03-01

    Scattering matrices are determined experimentally and used to study the low-amplitude interaction, between the acoustic and the hydrodynamic fields in a T-junction of rectangular ducts. In particular, combinations of grazing and bias flows are investigated in the study. It is observed that for all flow combinations, waves incident on the junction at the downstream side only are attenuated, while waves incident at the other branches may be amplified or attenuated, depending on the Strouhal number. When bias in-flow is introduced to a grazing flow, there is first an increase and then a decrease in both amplification and attenuation, as the bias in-flow Mach number is increased. Comparing with T-junctions of circular ducts, the interaction is stronger for rectangular duct junctions.

  1. Magnetohydrodynamic flow of generalized Maxwell fluids in a rectangular micropump under an AC electric field

    International Nuclear Information System (INIS)

    Zhao, Guangpu; Jian, Yongjun; Chang, Long; Buren, Mandula

    2015-01-01

    By using the method of separation of variables, an analytical solution for the magnetohydrodynamic (MHD) flow of the generalized Maxwell fluids under AC electric field through a two-dimensional rectangular micropump is reduced. By the numerical computation, the variations of velocity profiles with the electrical oscillating Reynolds number Re, the Hartmann number Ha, the dimensionless relaxation time De are studied graphically. Further, the comparison with available experimental data and relevant researches is presented. - Highlights: • MHD flow of the generalized Maxwell fluids under AC electric field is analyzed. • The MHD flow is confined to a two-dimensional rectangular micropump. • Analytical solution is obtained by using the method of separation of variables. • The influences of related parameters on the MHD velocity are discussed

  2. Rectangular Schlumberger resistivity arrays for delineating vadose zone clay-lined fractures in shallow tuff

    International Nuclear Information System (INIS)

    Miele, M.; Laymon, D.; Gilkeson, R.; Michelotti, R.

    1996-01-01

    Rectangular Schlumberger arrays can be used for 2-dimensional lateral profiling of apparent resistivity at a unique current electrode separation, hence single depth of penetration. Numerous apparent resistivity measurements are collected moving the potential electrodes (fixed MN spacing) within a rectangle of defined dimensions. The method provides a fast, cost-effective means for the collection of dense resistivity data to provide high-resolution information on subsurface hydrogeologic conditions. Several rectangular Schlumberger resistivity arrays were employed at Los Alamos National Laboratory (LANL) from 1989 through 1995 in an area adjacent to and downhill from an outfall pipe, septic tank, septic drainfield, and sump. Six rectangular arrays with 2 AB spacings were used to delineate lateral low resistivity anomalies that may be related to fractures that contain clay and/or vadose zone water. Duplicate arrays collected over a three year time period exhibited very good data repeatability. The properties of tritium make it an excellent groundwater tracer. Because tritium was present in discharged water from all of the anthropogenic sources in the vicinity it was used for this purpose. One major low resistivity anomaly correlates with relatively high tritium concentrations in the tuff. This was determined from borehole samples collected within and outside of the anomalous zone. The anomaly is interpreted to be due to fractures that contain clay from the soil profile. The clay was deposited in the fractures by aeolian processes and by surface water infiltration. The fractures likely served as a shallow vadose zone groundwater pathway

  3. Galilean invariant lattice Boltzmann scheme for natural convection on square and rectangular lattices

    NARCIS (Netherlands)

    Sman, van der R.G.M.

    2006-01-01

    In this paper we present lattice Boltzmann (LB) schemes for convection diffusion coupled to fluid flow on two-dimensional rectangular lattices. Via inverse Chapman-Enskog analysis of LB schemes including source terms, we show that for consistency with physics it is required that the moments of the

  4. A Analysis of the Low Frequency Sound Field in Non-Rectangular Enclosures Using the Finite Element Method.

    Science.gov (United States)

    Geddes, Earl Russell

    The details of the low frequency sound field for a rectangular room can be studied by the use of an established analytic technique--separation of variables. The solution is straightforward and the results are well-known. A non -rectangular room has boundary conditions which are not separable and therefore other solution techniques must be used. This study shows that the finite element method can be adapted for use in the study of sound fields in arbitrary shaped enclosures. The finite element acoustics problem is formulated and the modification of a standard program, which is necessary for solving acoustic field problems, is examined. The solution of the semi-non-rectangular room problem (one where the floor and ceiling remain parallel) is carried out by a combined finite element/separation of variables approach. The solution results are used to construct the Green's function for the low frequency sound field in five rooms (or data cases): (1) a rectangular (Louden) room; (2) The smallest wall of the Louden room canted 20 degrees from normal; (3) The largest wall of the Louden room canted 20 degrees from normal; (4) both the largest and the smallest walls are canted 20 degrees; and (5) a five-sided room variation of Case 4. Case 1, the rectangular room was calculated using both the finite element method and the separation of variables technique. The results for the two methods are compared in order to access the accuracy of the finite element method models. The modal damping coefficient are calculated and the results examined. The statistics of the source and receiver average normalized RMS P('2) responses in the 80 Hz, 100 Hz, and 125 Hz one-third octave bands are developed. The receiver averaged pressure response is developed to determine the effect of the source locations on the response. Twelve source locations are examined and the results tabulated for comparison. The effect of a finite sized source is looked at briefly. Finally, the standard deviation of the

  5. Two-Dimensional Mapping of the Calculated Fission Power for the Full-Size Fuel Plate Experiment Irradiated in the Advanced Test Reactor

    Science.gov (United States)

    Chang, G. S.; Lillo, M. A.

    2009-08-01

    The National Nuclear Security Administrations (NNSA) Reduced Enrichment for Research and Test Reactors (RERTR) program assigned to the Idaho National Laboratory (INL) the responsibility of developing and demonstrating high uranium density research reactor fuel forms to enable the use of low enriched uranium (LEU) in research and test reactors around the world. A series of full-size fuel plate experiments have been proposed for irradiation testing in the center flux trap (CFT) position of the Advanced Test Reactor (ATR). These full-size fuel plate tests are designated as the AFIP tests. The AFIP nominal fuel zone is rectangular in shape having a designed length of 21.5-in (54.61-cm), width of 1.6-in (4.064-cm), and uniform thickness of 0.014-in (0.03556-cm). This gives a nominal fuel zone volume of 0.482 in3 (7.89 cm3) per fuel plate. The AFIP test assembly has two test positions. Each test position is designed to hold 2 full-size plates, for a total of 4 full-size plates per test assembly. The AFIP test plates will be irradiated at a peak surface heat flux of about 350 W/cm2 and discharged at a peak U-235 burn-up of about 70 at.%. Based on limited irradiation testing of the monolithic (U-10Mo) fuel form, it is desirable to keep the peak fuel temperature below 250°C to achieve this, it will be necessary to keep plate heat fluxes below 500 W/cm2. Due to the heavy U-235 loading and a plate width of 1.6-in (4.064-cm), the neutron self-shielding will increase the local-to-average-ratio (L2AR) fission power near the sides of the fuel plates. To demonstrate that the AFIP experiment will meet the ATR safety requirements, a very detailed 2-dimensional (2D) Y-Z fission power profile was evaluated in order to best predict the fuel plate temperature distribution. The ability to accurately predict fuel plate power and burnup are essential to both the design of the AFIP tests as well as evaluation of the irradiated fuel performance. To support this need, a detailed MCNP Y

  6. Derivation and application of an analytical rock displacement solution on rectangular cavern wall using the inverse mapping method.

    Directory of Open Access Journals (Sweden)

    Mingzhong Gao

    Full Text Available Rectangular caverns are increasingly used in underground engineering projects, the failure mechanism of rectangular cavern wall rock is significantly different as a result of the cross-sectional shape and variations in wall stress distributions. However, the conventional computational method always results in a long-winded computational process and multiple displacement solutions of internal rectangular wall rock. This paper uses a Laurent series complex method to obtain a mapping function expression based on complex variable function theory and conformal transformation. This method is combined with the Schwarz-Christoffel method to calculate the mapping function coefficient and to determine the rectangular cavern wall rock deformation. With regard to the inverse mapping concept, the mapping relation between the polar coordinate system within plane ς and a corresponding unique plane coordinate point inside the cavern wall rock is discussed. The disadvantage of multiple solutions when mapping from the plane to the polar coordinate system is addressed. This theoretical formula is used to calculate wall rock boundary deformation and displacement field nephograms inside the wall rock for a given cavern height and width. A comparison with ANSYS numerical software results suggests that the theoretical solution and numerical solution exhibit identical trends, thereby demonstrating the method's validity. This method greatly improves the computing accuracy and reduces the difficulty in solving for cavern boundary and internal wall rock displacements. The proposed method provides a theoretical guide for controlling cavern wall rock deformation failure.

  7. Scattering of E Polarized Plane Wave by Rectangular Cavity With Finite Flanges

    Science.gov (United States)

    Vinogradova, Elena D.

    2017-11-01

    The rigorous Method of Regularization is implemented for accurate analysis of wave scattering by rectangular cavity with finite flanges. The solution is free from limitations on problem parameters. The calculation of the induced surface current, bistatic radar cross section (RCS) and frequency dependence of monostatic RCS are performed with controlled accuracy in a wide frequency band.

  8. Near field vorticity distributions from a sharp-edged rectangular jet

    International Nuclear Information System (INIS)

    Vouros, Alexandros P.; Panidis, Thrassos; Pollard, Andrew; Schwab, Rainer R.

    2015-01-01

    Highlights: • Axial mean vorticity equation terms are calculated from experimental data. • Appearance of ridges, dumbbell shape and saddleback velocity profiles is highlighted. • Explanations are provided using terms from the vorticity equation. - Abstract: Experimental results on the near field development of a free rectangular jet with aspect ratio 10 are presented. The jet issues from a sharp-edged orifice attached to a rectangular settling chamber at Re h ∼ 23,000, based on slot width, h. Measurements on cross plane grids were obtained with a two-component hot wire anemometry probe, which provided information on the three dimensional characteristics of the flow field. Two key features of this type of jet are mean axial velocity profiles presenting two off axis peaks, commonly mentioned as saddleback profiles, and a predominant dumbbell shape as described by, for example, a contour of the axial mean velocity. The saddleback shape is found to be significantly influenced by the vorticity distribution in the transverse plane of the jet, while the dumbbell is traced to two terms in the axial mean vorticity transport equation that diffuse fluid from the centre of the jet towards its periphery. At the farthest location where measurements were taken, 30 slot widths from the jet exit, the flow field resembles that of an axisymmetric jet

  9. The influence of streamwise vortices on turbulent heat transfer in rectangular ducts with various aspect ratios

    International Nuclear Information System (INIS)

    Choi, Hang Seok; Park, Tae Seon

    2013-01-01

    Highlights: ► With changing aspect ratio, the effect of secondary flows on the turbulent heat transfer is scrutinized by a LES. ► The conditional sampling technique of instantaneous near-wall streamwise vortices is developed. ► Clockwise and counter-clockwise rotating streamwise vortices are sampled and discussed with the wall heat transfer. ► The hot-sweep motions of CW and CCW vortices clearly appear with increasing aspect ratio. -- Abstract: The effect of aspect ratio of rectangular duct on the turbulent flow and heat transfer is very important for its engineering applications. But the turbulent thermal fields have not been fundamentally scrutinized in spite of its engineering significance especially for cooling device. Hence, in the present study, large eddy simulation is applied to the turbulent flow and heat transfer in rectangular ducts with varying aspect ratio. The turbulent statistics of the flow and thermal quantities are calculated and the characteristics of wall Nusselt number are investigated for each rectangular duct. Especially, to scrutinize near-wall streamwise vortices, a conditional sampling technique is developed and adopted. Clockwise and counter-clockwise rotating streamwise vortices are sampled and the probability density function of the vortex circulation Reynolds number and wall Nusselt number are calculated. From the results, the time-averaged secondary flow caused by instantaneous vortical motions has a great effect on the heat and momentum transport of the flow in the rectangular ducts. Hence, the wall Nusselt number is enhanced near the downwash flow region of the secondary flow. However, with increasing the aspect ratio, the effects of the hot-sweep flow of the clockwise and counter-clockwise rotating vortices become equally dominant near the wall normal bisector of the ducts. During time averaging process, these two counter-rotating vortices are canceled out each other diminishing a secondary flow but they still enhance the

  10. Analysis of pressure distribution originated over the external plate window of the RA-10 nuclear fuel

    International Nuclear Information System (INIS)

    Gramajo, M A; Garcia, J.C

    2012-01-01

    The RA10 is a pool type multipurpose research reactor. The core consists of a rectangular array of MTR fuel type. The refrigeration system at full power and normal operations conditions is carried out by an ascendant flow through the core. To ensure the refrigeration in the sub-channel formed between two adjacent fuels, there is a window orifice over the outer fuel plate. Part of the coolant flow that gets into the fuel will be derived by the window orifice to the sub-channel. Due to the change in the coolant flow direction is necessary to establish the pressure distribution originated over the window In order to achieve this goal a CFD commercial code (FLUENT v6.3.26) was used to perform numerical simulations to obtain the pressure distribution over the window. A quarter of the fuel was modeled using proper symmetry and boundaries conditions (author)

  11. Droplet size in a rectangular Venturi scrubber

    Directory of Open Access Journals (Sweden)

    M. A. M. Costa

    2004-06-01

    Full Text Available The Venturi scrubber is a device which uses liquid in the form of droplets to efficiently remove fine particulate matter from gaseous streams. Droplet size is of fundamental importance for the scrubber performance. In the present experimental study, a laser diffraction technique was used in order to measure droplet size in situ in a Venturi scrubber with a rectangular cross section. Droplet size distribution was measured as a function of gas velocity (58.3 to 74.9 m/s, liquid-to-gas ratio (0.07 to 0.27 l/m³, and distance from liquid injection point (64 to 173 mm. It was found that all these variables significantly affect droplet size. The results were compared with the predictions from correlations found in the literature.

  12. Regionalization of the Modified Bartlett-Lewis Rectangular Pulse Stochastic Rainfall Model

    OpenAIRE

    Dongkyun Kim; Francisco Olivera; Huidae Cho; Scott A. Socolofsky

    2013-01-01

    Parameters of the Modified Bartlett-Lewis Rectangular Pulse (MBLRP) stochastic rainfall simulation model were regionalized across the contiguous United States. Three thousand four hundred forty-four National Climate Data Center (NCDC) rain gauges were used to obtain spatial and seasonal patterns of the model parameters. The MBLRP model was calibrated to minimize the discrepancy between the precipitation depth statistics between the observed and MBLRP-generated precipitation time series. These...

  13. Diffusion of heat from a finite, rectangular, plane heat source

    International Nuclear Information System (INIS)

    Ferreri, J.C.; Caballero, C.H.

    1985-01-01

    Non-dimensional results for the temperature field originating in a rectangular, finite, plane heat source with infinitesimal thickness are introduced. The source decays in time, zero decay being a particular case. Results are useful for obtaining an aproximation of the maximum temperature of a system holding an internal heat source. The range selected for the parameters is specially useful in the case of a nuclear waste repository. The application to the case of mass diffussion arises from analogy. (Author) [es

  14. A Possible Differentially Shortened Strike-slip Plate Boundary: the Okhotsk Plate Example.

    Science.gov (United States)

    Hindle, D.; Egorov, V.; Mackey, K. G.; Fujita, K.

    2004-12-01

    The Okhotsk plate has been postulated based on a combination of GPS geodetic inversions (REVEL1), seimsicity, geologic and lineament data. Lying between the North American and Eurasian plates, its northwestern corner would appear to be undergoing compression in a scissors motion between the two bounding plates. Extrusion tectonics along multiple, large strike-slip faults within the Okhotsk plate itself have been suggested to allow the escape of material away from the apex of Eurasia-North America. The plate boundary between Okhotsk and North America has been suggested to be diffuse, based on widely scattered minor seismicity. However, the large, left lateral, Ulakhan fault has also been suggested as a candidate plate boundary. We present field geological and geomorphological evidence of the partitioning of deformation between the Ulakhan fault, and several parallel and oblique, linked faults. The Ulakhan fault strand appears to have a maximum displacement of 24 km based on river valley offsets and closing large pull apart basins. Some of the displacement from the Ulakhan fault appears relayed into the plate margin along oblique trending, thrust/oblique slip faults. Estimated shortening over these faults is equivalent to the amount of shortening relayed into the plate margin from the plate boundary. There may be several thrust/oblique slip faults along the Ulakhan fault, which leads to the interesting situation of a segmented, strike-slip plate boundary being actively shortened in a margin parallel direction. This may be the result of postulated extrusion of the Okhotsk plate due to North America/Eurasia convergence. Such a situation would have important consequences for the interpretation of GPS data in a plate tectonic context.

  15. Quantitative study of rectangular waveguide behavior in the THz.

    Energy Technology Data Exchange (ETDEWEB)

    Rowen, Adam M.; Nordquist, Christopher Daniel; Wanke, Michael Clement

    2009-10-01

    This report describes our efforts to quantify the behavior of micro-fabricated THz rectangular waveguides on a configurable, robust semiconductor-based platform. These waveguides are an enabling technology for coupling THz radiation directly from or to lasers, mixers, detectors, antennas, and other devices. Traditional waveguides fabricated on semiconductor platforms such as dielectric guides in the infrared or co-planar waveguides in the microwave regions, suffer high absorption and radiative losses in the THz. The former leads to very short propagation lengths, while the latter will lead to unwanted radiation modes and/or crosstalk in integrated devices. This project exploited the initial developments of THz micro-machined rectangular waveguides developed under the THz Grand Challenge Program, but instead of focusing on THz transceiver integration, this project focused on exploring the propagation loss and far-field radiation patterns of the waveguides. During the 9 month duration of this project we were able to reproduce the waveguide loss per unit of length in the waveguides and started to explore how the loss depended on wavelength. We also explored the far-field beam patterns emitted by H-plane horn antennas attached to the waveguides. In the process we learned that the method of measuring the beam patterns has a significant impact on what is actually measured, and this may have an effect on most of the beam patterns of THz that have been reported to date. The beam pattern measurements improved significantly throughout the project, but more refinements of the measurement are required before a definitive determination of the beam-pattern can be made.

  16. Finite element modeling of tornado missile impact on reinforced concrete wall panels

    International Nuclear Information System (INIS)

    Zhang, Y.; Vallabhan, C.V.G.; McDonald, J.R.

    1993-01-01

    This paper describes a finite element model for the impact of large tornado-generated missiles with reinforced concrete wall panels. The analysis predicts the dynamic response of a wall panel when impacted by a missile with a large contact area such as an automobile. Quadratic finite elements are used to discretize the domain of the wall panel. Fundamental assumptions are based on the Mindlin and the related Reinsser plate theories. An 'embedded' model is employed to account for the reinforcing bars. The nonlinear behavior of concrete and steel bars are analyzed by means of time-dependent constitutive relationships. A model is proposed to describe the initial and subsequent yield surfaces of concrete material, which avoids underestimation of the effect of high hydrostatic stresses on the yielding behavior of concrete. Ottosen's four-parameter failure criterion is used to define the failure surface of concrete. A crack monitoring algorithm accounts for post-cracking and post-crushing behavior of concrete. Explicit time step integration of nonlinear dynamic equations are carried out using the finite element discretization of a concrete wall panel. As a practical application of the analysis technique, the contact failure pressure for a particular panel geometry can be calculated. The contact failure pressure and the elapsed time to failure after missile contact define a rectangular or triangular impulse loading to produce failure of the panel. Since automobile crashes are known to produce triangular impulse loads, the two pulses (failure and impact) can be compared to determine if a particular impact will fail the panels. Thus, a particular concrete panel can be analyzed to determine if it will fail under a postulated missile impact

  17. Development of New Correlation and Assessment of Correlations for Two-Phase Pressure Drop in Rectangular Microchannels

    International Nuclear Information System (INIS)

    Choi, Chi Woong; Yu, Dong In; Kim, Moo Hwan

    2010-01-01

    There are two kinds of models in two-phase pressured drop; homogeneous flow model and separated flow model. Many previous researchers have developed correlations for two-phase pressure drop in a microchannel. Most correlations were modified Lockhart and Martinelli's correlation, which was based on the separated flow model. In this study, experiments for adiabatic liquid water and nitrogen gas flow in rectangular microchannels were conducted to investigate two-phase pressure drop in the rectangular microchannels. Two-phase frictional pressure drop in the rectangular microchannels is highly related with flow regime. Homogeneous model with six two-phase viscosity models: Owen(21)'s, MacAdams(22)'s, Cicchitti et al.(23)'s, Dukler et al.(24)'s, Beattie and Whalley(25)'s, Lin et al.(26)'s models and six separated flow models: Lockhart and Martinelli(27)'s, Chisholm(31)'s, Zhang et al.(15)'s, Lee and Lee(5)'s, Moriyama and Inue(4)'s, Qu and Mudawar(8)'s models were assessed with our experimental data. The best two-phase viscosity model is Beattie and Whalley's model. The best separated flow model is Qu and Mudawar's correlation. Flow regime dependency in both homogeneous and separated flow models was observed. Therefore, new flow pattern based correlations for both homogeneous and separated flow models were individually proposed

  18. An Aligned-Gap and Centered-Gap Rectangular Multiple Split Ring Resonator for Dielectric Sensing Applications

    Directory of Open Access Journals (Sweden)

    Izyani Mat Rusni

    2014-07-01

    Full Text Available This paper presents the design and development of a planar Aligned-Gap and Centered-Gap Rectangular Multiple Split Ring Resonator (SRR for microwave sensors that operates at a resonance frequency around 5 GHz. The sensor consists of a microstrip transmission line loaded with two elements of rectangular SRR on both sides. The proposed metamaterial sensors were designed and fabricated on Rogers RT5880 substrate having dielectric constant of 2.2 and thickness of 0.787 mm. The final dimension of the proposed sensor was measured at 35 × 14 mm2. Measured results show good agreement with simulated ones as well as exhibiting high Q-factor for use in sensing application. A remarkably shift of resonance frequency is observed upon introduction of several sample with different dielectric value.

  19. The Effect of Mandrel Configuration on the Warpage in Pultrusion of Rectangular Hollow Profiles

    NARCIS (Netherlands)

    Baran, Ismet; Hattel, Jesper H.; Akkerman, Remko

    2014-01-01

    Thermo-mechanical process simulation of an industrially pultruded rectangular hollow profile is presented. Glass/polyester is used for the continuous filament mat (CFM) and the uni-directional (UD) layers. The process induced residual distortions together with the temperature and degree of cure are

  20. Effect of Plate Curvature on Blast Response of Structural Steel Plates

    Science.gov (United States)

    Veeredhi, Lakshmi Shireen Banu; Ramana Rao, N. V.; Veeredhi, Vasudeva Rao

    2018-04-01

    In the present work an attempt is made, through simulation studies, to determine the effect of plate curvature on the blast response of a door structure made of ASTM A515 grade 50 steel plates. A door structure with dimensions of 5.142 m × 2.56 m × 10 mm having six different radii of curvatures is analyzed which is subjected to blast load. The radii of curvature investigated are infinity (flat plate), 16.63, 10.81, 8.26, 6.61 and 5.56 m. In the present study, a stand-off distance of 11 m is considered for all the cases. Results showed that the door structure with smallest radius of curvature experienced least plastic deformation and yielding when compared to a door with larger radius of curvature with same projected area. From the present Investigation, it is observed that, as the radius of curvature of the plate increases, the deformation mode gradually shifts from indentation mode to flexural mode. The plates with infinity and 16.63 m radius of curvature have undergone flexural mode of deformation and plates with 6.61 and 5.56 m radius of curvature undergo indentation mode of deformation. Whereas, mixed mode of deformation that consists of both flexural and indentation mode of deformations are seen in the plates with radius of curvature 10.81 and 8.26 m. As the radius of curvature of the plate decreases the ability of the plate to mitigate the effect the blast loads increased. It is observed that the plate with smaller radius of curvature deflects most of the blast energy and results in least indentation mode of deformation. The most significant observation made in the present investigation is that the strain energy absorbed by the steel plate gets reduced to 1/3 rd when the radius of curvature is approximately equal to the stand-off distance which could be the critical radius of curvature.

  1. The Okhotsk Plate and the Eurasia-North America plate boundary zone.

    Science.gov (United States)

    Hindle, David; Mackey, Kevin

    2014-05-01

    The Eurasia-North America plate boundary zone transitions from spreading at rates of ~ 25mm/yr in the North Atlantic, to compression at rates of ~ 5mm/yr in the region of the Okhotsk plate. Because the pole of rotation between Eurasia and North America lies more or less on their mutual boundary, there is a linear change in rate along the boundary, and regions near the euler pole are subject to extremely low deformation rates. The Okhotsk - Eurasia - North America triple junction lies slightly south of the rotation pole, placing the Okhotsk plate entirely in a weakly contractional setting. Regions near the triple junction absorb 1mm/yr contraction. Further south, towards the shoreline of the Okhotsk sea, up to 5 mm/yr contraction may be absorbed within the plate. How shortening is accommodated across the boundary remains an open question. One possibility is wholesale extrusion of the entire Okhotsk plate (or possibly its northwestern corner) along two plate boundary strike slip faults (Eurasia-Okhostk and North America Okhotsk). The problem with this model is that the seismic record does not presently clearly support it, with the largest events distributed both within the plate interior and on its boundaries. This may suggest that instead, the Okhotsk plate, and particularly its north-western end, consists of a series of smaller blocks which shuffle against each other, partially accommodating extrusion, but also permitting some internal deformation and change of shape of the Okhotsk plate itself. We present analyses of the very sparse seismic record from the region, as well as geometric-kinematic, tectonic models of the possible deformation of northwest Okhotsk to try to better understand the different probabilities of how this slowly deforming plate boundary zone is behaving.

  2. Modeling the interference of vortex-induced vibration and galloping for a slender rectangular prism

    Science.gov (United States)

    Mannini, Claudio; Massai, Tommaso; Marra, Antonino Maria

    2018-04-01

    Several bluff bodies in an airflow, such as rectangular cylinders with moderate side ratio, in particular conditions of mass and damping can experience the interference of vortex-induced vibration (VIV) and galloping. This promotes a combined instability, which one may call "unsteady galloping", with peculiar features and possibly large vibration amplitudes in flow speed ranges where no excitation is predicted by classical theories. The mathematical model proposed between the 70's and the 80's by Prof. Y. Tamura to simulate this phenomenon was considered here for the case study of a two-dimensional rectangular cylinder with a side ratio of 1.5, having the shorter section side perpendicular to the smooth airflow. This wake-oscillator model relies on the linear superposition of the unsteady wake force producing VIV excitation and the quasi-steady force that is responsible for galloping. The model formulation was slightly modified, and the way to determine a crucial parameter was changed, revealing a previously unexplored behavior of the equations. In the present form, the model is able to predict the dynamic response of the rectangular cylinder with a satisfactory qualitative and, to a certain extent, quantitative agreement with the experimental data, although the limitations of the present approach are clearly highlighted in the paper. The mathematical modeling of unsteady galloping and the analysis of the results offer a deep insight into this complicated phenomenon and its nonlinear features. The model also represents a useful engineering tool to estimate the vibration of a structure or structural element for which the interference of VIV and galloping is envisaged.

  3. Discharge coefficient of a rectangular sharp-edged broad-crested weir

    OpenAIRE

    Zachoval Zbyněk; Knéblová Michaela; Roušar Ladislav; Rumann Ján; Šulc Jan

    2014-01-01

    his paper is concerned with the determination of the relationship for the calculation of the discharge coefficient at free overflow over a rectangular sharp-edged broad-crested weir without lateral contraction. The determination was made on the basis of new measurement in a range of the relative thickness of the weir from 0.12 to 0.30 and newly in a large range of relative height of the weir extremely from 0.24 to 6.8 which greatly expands the application possibilities of low weirs. In additi...

  4. A novel compact low impedance Marx generator with quasi-rectangular pulse output

    Science.gov (United States)

    Liu, Hongwei; Jiang, Ping; Yuan, Jianqiang; Wang, Lingyun; Ma, Xun; Xie, Weiping

    2018-04-01

    In this paper, a novel low impedance compact Marx generator with near-square pulse output based on the Fourier theory is developed. Compared with the traditional Marx generator, capacitors with different capacity have been used. It can generate a high-voltage quasi-rectangular pulse with a width of 100 ns at low impedance load, and it also has high energy density and power density. The generator consists of 16 modules. Each module comprises an integrative single-ended plastic case capacitor with a nominal value of 54 nF, four ceramic capacitors with a nominal value of 1.5 nF, a gas switch, a charging inductor, a grounding inductor, and insulators which provide mechanical support for all elements. In the module, different discharge periods from different capacitors add to the main circuit to form a quasi-rectangular pulse. The design process of the generator is analyzed, and the test results are provided here. The generator achieved pulse output with a rise time of 32 ns, pulse width of 120 ns, flat-topped width (95%-95%) of 50 ns, voltage of 550 kV, and power of 20 GW.

  5. Numerical investigation of flow past a row of rectangular rods

    Directory of Open Access Journals (Sweden)

    S.Ul. Islam

    2016-09-01

    Full Text Available A numerical study of uniform flow past a row of rectangular rods with aspect ratio defined as R = width/height = 0.5 is performed using the Lattice Boltzmann method. For this study the Reynolds number (Re is fixed at 150, while spacings between the rods (g are taken in the range from 1 to 6. Depending on g, the flow is classified into four patterns: flip-flopping, nearly unsteady-inphase, modulated inphase-antiphase non-synchronized and synchronized. Sudden jumps in physical parameters were observed, attaining either maximum or minimum values, with the change in flow patterns. The mean drag coefficient (Cdmean of middle rod is higher than the second and fourth rod for flip-flopping pattern while in case of nearly unsteady-inphase the middle rod attains minimum drag coefficient. It is also found that the Strouhal number (St of first, second and fifth rod decreases as g increases while that of other two have mixed trend. The results further show that there exist secondary interaction frequencies together with primary vortex shedding frequency due to jet in the gap between rods for 1 ⩽ g ⩽ 3. For the average values of Cdmean and St, an empirical relation is also given as a function of gap spacing. This relation shows that the average values of Cdmean and St approach to those of single rectangular rod with increment in g.

  6. Plate removal following orthognathic surgery.

    Science.gov (United States)

    Little, Mhairi; Langford, Richard Julian; Bhanji, Adam; Farr, David

    2015-11-01

    The objectives of this study are to determine the removal rates of orthognathic plates used during orthognathic surgery at James Cook University Hospital and describe the reasons for plate removal. 202 consecutive orthognathic cases were identified between July 2004 and July 2012. Demographics and procedure details were collected for these patients. Patients from this group who returned to theatre for plate removal between July 2004 and November 2012 were identified and their notes were analysed for data including reason for plate removal, age, smoking status, sex and time to plate removal. 3.2% of plates were removed with proportionally more plates removed from the mandible than the maxilla. 10.4% of patients required removal of one or more plate. Most plates were removed within the first post-operative year. The commonest reasons for plate removal were plate exposure and infection. The plate removal rates in our study are comparable to those seen in the literature. Copyright © 2015 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  7. An analytical solution for Dean flow in curved ducts with rectangular cross section

    Science.gov (United States)

    Norouzi, M.; Biglari, N.

    2013-05-01

    In this paper, a full analytical solution for incompressible flow inside the curved ducts with rectangular cross-section is presented for the first time. The perturbation method is applied to solve the governing equations and curvature ratio is considered as the perturbation parameter. The previous perturbation solutions are usually restricted to the flow in curved circular or annular pipes related to the overly complex form of solutions or singularity situation for flow in curved ducts with non-circular shapes of cross section. This issue specifies the importance of analytical studies in the field of Dean flow inside the non-circular ducts. In this study, the main flow velocity, stream function of lateral velocities (secondary flows), and flow resistance ratio in rectangular curved ducts are obtained analytically. The effect of duct curvature and aspect ratio on flow field is investigated as well. Moreover, it is important to mention that the current analytical solution is able to simulate the Taylor-Görtler and Dean vortices (vortices in stable and unstable situations) in curved channels.

  8. A Novel Transcranial Magnetic Stimulator Inducing Near Rectangular Pulses with Controllable Pulse Width (cTMS)

    Science.gov (United States)

    Jalinous, Reza; Lisanby, Sarah H.

    2013-01-01

    A novel transcranial magnetic stimulation (TMS) device with controllable pulse width (PW) and near rectangular pulse shape (cTMS) is described. The cTMS device uses an insulated gate bipolar transistor (IGBT) with appropriate snubbers to switch coil currents up to 7 kA, enabling PW control from 5 μs to over 100 μs. The near-rectangular induced electric field pulses use 22–34% less energy and generate 67–72% less coil heating compared to matched conventional cosine pulses. CTMS is used to stimulate rhesus monkey motor cortex in vivo with PWs of 20 to 100 μs, demonstrating the expected decrease of threshold pulse amplitude with increasing PW. The technological solutions used in the cTMS prototype can expand functionality, and reduce power consumption and coil heating in TMS, enhancing its research and therapeutic applications. PMID:18232369

  9. Prediction of the critical heat flux for saturated upward flow boiling water in vertical narrow rectangular channels

    International Nuclear Information System (INIS)

    Choi, Gil Sik; Chang, Soon Heung; Jeong, Yong Hoon

    2016-01-01

    A study, on the theoretical method to predict the critical heat flux (CHF) of saturated upward flow boiling water in vertical narrow rectangular channels, has been conducted. For the assessment of this CHF prediction method, 608 experimental data were selected from the previous researches, in which the heated sections were uniformly heated from both wide surfaces under the high pressure condition over 41 bar. For this purpose, representative previous liquid film dryout (LFD) models for circular channels were reviewed by using 6058 points from the KAIST CHF data bank. This shows that it is reasonable to define the initial condition of quality and entrainment fraction at onset of annular flow (OAF) as the transition to annular flow regime and the equilibrium value, respectively, and the prediction error of the LFD model is dependent on the accuracy of the constitutive equations of droplet deposition and entrainment. In the modified Levy model, the CHF data are predicted with standard deviation (SD) of 14.0% and root mean square error (RMSE) of 14.1%. Meanwhile, in the present LFD model, which is based on the constitutive equations developed by Okawa et al., the entire data are calculated with SD of 17.1% and RMSE of 17.3%. Because of its qualitative prediction trend and universal calculation convergence, the present model was finally selected as the best LFD model to predict the CHF for narrow rectangular channels. For the assessment of the present LFD model for narrow rectangular channels, effective 284 data were selected. By using the present LFD model, these data are predicted with RMSE of 22.9% with the dryout criterion of zero-liquid film flow, but RMSE of 18.7% with rivulet formation model. This shows that the prediction error of the present LFD model for narrow rectangular channels is similar with that for circular channels.

  10. Bubble departure diameter in narrow rectangular channel under rolling condition

    Energy Technology Data Exchange (ETDEWEB)

    Xie, T.; Chen, B.; Yan, X.; Xu, J.; Huang, Y.; Xiao, Z. [Nuclear Power Inst. of China, Chengdu, Sichuan (China)

    2014-07-01

    Forced convective subcooled boiling flow experiments were conducted in a vertical upward narrow rectangular channel under rolling motion. A high-speed digital video camera was used to capture the dynamics of the bubble nucleation process. Bubble departure diameters were obtained from the images. A bubble departure model based on force balance analysis was proposed to predict the bubble departure size under rolling condition by considering the additional centrifugal, tangential and Coriolis force. The proposed model agreed well with the experimental data within the averaged relative deviation of 5%. (author)

  11. Experimental studies of rectangular tube absorber photovoltaic thermal collector with various types of nanofluids under the tropical climate conditions

    International Nuclear Information System (INIS)

    Al-Shamani, Ali Najah; Sopian, K.; Mat, Sohif; Hasan, Husam Abdulrasool; Abed, Azher M.; Ruslan, M.H.

    2016-01-01

    Highlights: • A new rectangular tube as absorber for the PVT solar collector was developed. • Different types of nanofluids (SiO_2, TiO_2 and SiC) evaluated. • η_e_l PVT SiC nanofluid was 13.52% at 1000 W/m"2 and flow rate of 0.17 kg/s. • η_c_o_m_b_i_n_e_d PVT SiC nanofluid was 81.73% at 1000 W/m"2 and flow rate of 0.17 kg/s. - Abstract: The flat plate photovoltaic thermal (PVT) collectors can be classified into the type of working fluids used namely the water based PVT collectors, air based PVT collectors and combination of water/air PVT collectors. However, low thermal conductivity of the working fluids has always been the primary limitation in the development of energy-efficient heat transfer fluids, and higher collector performance. To overcome this limitation, there is a strong motivation to improve the heat transfer of fluids with higher thermal conductivity. This new generation of heat transfer fluids called nanofluids consists of suspended nanoparticles and has higher suspension stability compared to the millimeter or micrometer size nanoparticles. Thus, the heat transfer characteristics will be enhanced by using nanofluids. The PVT collector has been designed, fabricated and tested outdoor under the Malaysia tropical climate conditions. The PVT collector consists of specially designed rectangular tube absorber (stainless steel material, height of 15 mm, width of 25 mm and thickness of 1 mm) attached under the photovoltaic module. The PVT collector was experimentally tested with different types of nanofluids (SiO_2, TiO_2 and SiC). The results indicated that the PVT collector with SiC nanofluid has the highest combined photovoltaic thermal (PVT) efficiency of 81.73% and PVT electrical efficiency of 13.52% with the best overall energy coefficient (COE) of 0.93 has been achieved at a flow rate of 0.170 kg/s and solar irradiance levels of 1000 W/m"2, followed by PVT-TiO_2 nanofluids, PVT-SiO_2 nanofluids, and PVT-water respectively.

  12. Thermoelectric effects in a rectangular Aharonov-Bohm geometry

    Science.gov (United States)

    Pye, A. J.; Faux, D. A.; Kearney, M. J.

    2016-04-01

    The thermoelectric transport properties of a rectangular Aharonov-Bohm ring at low temperature are investigated using a theoretical approach based on Green's functions. The oscillations in the transmission coefficient as the field is varied can be used to tune the thermoelectric response of the ring. Large magnitude thermopowers are obtainable which, in conjunction with low conductance, can result in a high thermoelectric figure of merit. The effects of single site impurities and more general Anderson disorder are considered explicitly in the context of evaluating their effect on the Fano-type resonances in the transmission coefficient. Importantly, it is shown that even for moderate levels of disorder, the thermoelectric figure of merit can remain significant, increasing the appeal of such structures from the perspective of specialist thermoelectric applications.

  13. Effect of analysis parameters on non-linear implicit finite element analysis of marine corroded steel plate

    Science.gov (United States)

    Islam, Muhammad Rabiul; Sakib-Ul-Alam, Md.; Nazat, Kazi Kaarima; Hassan, M. Munir

    2017-12-01

    FEA results greatly depend on analysis parameters. MSC NASTRAN nonlinear implicit analysis code has been used in large deformation finite element analysis of pitted marine SM490A steel rectangular plate. The effect of two types actual pit shape on parameters of integrity of structure has been analyzed. For 3-D modeling, a proposed method for simulation of pitted surface by probabilistic corrosion model has been used. The result has been verified with the empirical formula proposed by finite element analysis of steel surface generated with different pitted data where analyses have been carried out by the code of LS-DYNA 971. In the both solver, an elasto-plastic material has been used where an arbitrary stress versus strain curve can be defined. In the later one, the material model is based on the J2 flow theory with isotropic hardening where a radial return algorithm is used. The comparison shows good agreement between the two results which ensures successful simulation with comparatively less energy and time.

  14. Experimental study on saturated boiling of two phase natural circulation under low pressure in narrow rectangular channels

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zi-chao; Qi, Shi; Zhou, Tao; Li, Bing; Shahzad, Muhammad Ali [North China Electric Power Univ., Beijing (China). School of Nuclear Science and Engineering; Beijing Key Laboratory of Passive Safety Technology for Nuclear Energy, Beijing (China); Huang, Yan-ping [Nuclear Reactor Thermal Hydraulics Technology, Chengdu (China). CNNC Key Lab.

    2017-12-15

    Saturated boiling of two-phase natural circulation has been experimentally investigated based on a natural circulation device with narrow rectangular channels. When heating power reaches a certain range, it is possible to observe the phenomenon of saturated boiling and flow pattern transition in the system. The results show the heat transfer coefficient of saturated boiling decreases with the increasing of pressure, heating power and size of narrow rectangle channels. The buoyancy force causing mixed convection decreases the heat transfer coefficient. Finally, a dimensionless number is introduced, which reflects length to width ratio of rectangular narrow section and Rayleigh number, in order to revise the presented correlation. All errors fall within the range of ±15%.

  15. Development of an innovative plate-type SG for fast breeder reactor. Proposal of the concept and the evaluation of the fabricating method by the test fabrication of the partial model

    International Nuclear Information System (INIS)

    Nishi, Yoshihisa; Kinoshita, Izumi

    2006-01-01

    The concept of an innovative plate type SG for the fast reactor fabricated by using the HIP (Hot Isostatic Pressing) method was proposed. The heat transfer plate, which is assembled with rectangular tubes and is fabricated by HIP method, is surrounded by leakage detection spaces. It is possible to apply it to both the pool-type and the loop-type LMFR. In this report, the fabrication technique was studied about the concept for the loop-type LMFR, and the following results were obtained. Hip tests, tensile tests, and structure observation were performed to clarify the suitable HIP condition for the modified 9Cr-1Mo steel. As a result, the optimum condition of 1150 deg C x 1200 kgf/cm 2 x 3 hr was found. Nickel-type solder (BNi-5) and gold-type solder (BAu-4) were selected as a joining material to laminate the heat transfer tube plates. Through the comparison of tensile tests, BAu-4 that showed a more excellent joining performance was selected on the assumption of the margin of 5 mm from the welding line. After buckling load had been clarified, the BAu-4 brazing of the heat transfer tube plates was performed using a hot pressing method. Problems were not observed in the welding of simulated header, and in the fabricating of the partial model of SG. (author)

  16. Finite-size resonance dielectric cylinder in a rectangular waveguide

    International Nuclear Information System (INIS)

    Chuprina, V.N.; Khizhnyak, N.A.

    1988-01-01

    The problem on resonance spread of an electromagnetic wave by a dielectric circular cylinder of finite size in a rectangular waveguide is solved by a numerical-analytical method. The cylinder axes are parallel. The cylinder can be used as a resonance tuning element in accelerating SHF-sections. Problems on cutting off linear algebraic equation systems, to which relations of macroscopic electrodynamics in the integral differential form written for the concrete problem considered here are reduced by analytical transformations, are investigated in the stage of numerical analysis. Theoretical dependences of the insertion of the voltage standing wave coefficient on the generator wave length calculated for different values of problem parameters are constracted

  17. Smart wave filtering method of a rectangular panel using Hilbert transformers and its application to an adaptive control system

    International Nuclear Information System (INIS)

    Iwamoto, Hiroyuki; Tanaka, Nobuo; Hill, Simon G

    2010-01-01

    This paper concerns the active vibration control of a rectangular panel using smart sensors from the viewpoint of an active wave control theory. The objective of this paper is to present a new type of filter which enables the measurement of the wave amplitude of a rectangular panel in real time for the application of an adaptive feedforward control system which inactivates vibration modes. Firstly, a novel wave filtering method using smart PVDF sensors is proposed. It is found that the shaping function of smart sensors is a complex function. To realize the smart sensor in a practical situation, a Hilbert transformer is utilized to implement a phase shifter of 90° for broadband frequencies. Then, from the viewpoint of a numerical analysis, the characteristics of the proposed wave filter and the performance of the adaptive feedforward control system using the wave filter are discussed. Finally, experiments implementing the active wave control theory which uses the proposed wave filter are conducted, demonstrating the validity of the proposed method in suppressing the vibration of a rectangular panel

  18. Research on the Cross Section Precision of High-strength Steel Tube with Rectangular Section in Rotary Draw Bending

    Science.gov (United States)

    Yang, Hongliang; Zhao, Hao; Xing, Zhongwen

    2017-11-01

    For the demand of energy conservation and security improvement, high-strength steel (HSS) is increasingly being used to produce safety related automotive components. However, cross-section distortion occurs easily in bending of HSS tube with rectangular section (RS), affecting the forming precision. HSS BR1500HS tube by rotary draw bending is taken as the study object and a description method of cross-section distortion is proposed in this paper. The influence on cross-section precision of geometric parameters including cross-section position, thickness of tube, bend radius etc. are studied by experiment. Besides, simulation of the rotary draw bending of HSS tube with rectangular section by ABAQUS are carried out and compared to the experiment. The results by simulation agree well with the experiment and show that the cross-section is approximately trapezoidal after distortion; the maximum of distortion exists at 45 ∼ 60° of the bending direction; and the absolute and relative distortion values increase with the decreasing of tube thickness or bending radius. Therefore, the results can provide a reference for the design of geometric parameters of HSS tube with rectangular section in rotary draw bending.

  19. Cadmium plating replacements

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, M.J.; Groshart, E.C.

    1995-03-01

    The Boeing Company has been searching for replacements to cadmium plate. Two alloy plating systems seem close to meeting the needs of a cadmium replacement. The two alloys, zinc-nickel and tin-zinc are from alloy plating baths; both baths are neutral pH. The alloys meet the requirements for salt fog corrosion resistance, and both alloys excel as a paint base. Currently, tests are being performed on standard fasteners to compare zinc-nickel and tin-zinc on threaded hardware where cadmium is heavily used. The Hydrogen embrittlement propensity of the zinc-nickel bath has been tested, and just beginning for the tin-zinc bath. Another area of interest is the electrical properties on aluminum for tin-zinc and will be discussed. The zinc-nickel alloy plating bath is in production in Boeing Commercial Airplane Group for non-critical low strength steels. The outlook is promising that these two coatings will help The Boeing Company significantly reduce its dependence on cadmium plating.

  20. History of internal fixation with plates (part 2): new developments after World War II; compressing plates and locked plates.

    Science.gov (United States)

    Hernigou, Philippe; Pariat, Jacques

    2017-07-01

    The first techniques of operative fracture with plates were developed in the 19th century. In fact, at the beginning these methods consisted of an open reduction of the fracture usually followed by a very unstable fixation. As a consequence, the fracture had to be opened with a real risk of (sometimes lethal) infection, and due to unstable fixation, protection with a cast was often necessary. During the period between World Wars I and II, plates for fracture fixation developed with great variety. It became increasingly recognised that, because a fracture of a long bone normally heals with minimal resorption at the bone ends, this may result in slight shortening and collapse, so a very rigid plate might prevent such collapse. However, as a consequence, delayed healing was observed unless the patient was lucky enough to have the plate break. One way of dealing with this was to use a slotted plate in which the screws could move axially, but the really important advance was recognition of the role of compression. After the first description of compression by Danis with a "coapteur", Bagby and Müller with the AO improved the technique of compression. The classic dynamic compression plates from the 1970s were the key to a very rigid fixation, leading to primary bone healing. Nevertheless, the use of strong plates resulted in delayed union and the osteoporosis, cancellous bone, comminution, and/or pathological bone resulted in some failures due to insufficient stability. Finally, new devices represented by locking plates increased the stability, contributing to the principles of a more biological osteosynthesis while giving enough stability to allow immediate full weight bearing in some patients.

  1. Analysis of fatigue resistance of continuous and non-continuous welded rectangular frame intersections by finite element method

    International Nuclear Information System (INIS)

    McCoy, M. L.; Moradi, R.; Lankarani, H. M.

    2011-01-01

    Agricultural and construction equipment are commonly implemented with rectangular tubing in their structural frame designs. A typical joining method to fabricate these frames is by welding and the use of ancillary structural plating at the connections. This aids two continuous members to pass through an intersection point of the frame with some degree of connectivity, but the connections are highly unbalanced as the tubing centroids exhibit asymmetry. Due to the practice of welded continuous member frame intersections in current agricultural equipment designs, a conviction may exist that welded continuous member frames are superior in structural strength over that of structural frame intersections implementing welded non-continuous members where the tubing centroids lie within two planes of symmetry, a connection design that would likely fabricating a more fatigue resistant structural frame. Three types of welded continuous tubing frame intersections currently observed in the designs of agricultural equipment were compared to two non-continuous frame intersection designs. Each design was subjected to the same loading condition and then examined for stress levels using the Finite Element Method to predict fatigue life. Results demonstrated that a lighter weight, non-continuous member frame intersection design was two magnitudes superior in fatigue resistance than some current implemented frame designs when using Stress-Life fatigue prediction methods and empirical fatigue strengths for fillet welds. Stress-Life predictions were also made using theoretical fatigue strength calculations for the fatigue strength at the welds for comparison to the empirical derived weld fatigue strength

  2. Computational Fluid Dynamic Pressure Drop Estimation of Flow between Parallel Plates

    Energy Technology Data Exchange (ETDEWEB)

    Son, Hyung Min; Yang, Soo Hyung; Park, Jong Hark [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-10-15

    Many pool type reactors have forced downward flows inside the core during normal operation; there is a chance of flow inversion when transients occur. During this phase, the flow undergo transition between turbulent and laminar regions where drastic changes take place in terms of momentum and heat transfer, and the decrease in safety margin is usually observed. Additionally, for high Prandtl number fluids such as water, an effect of the velocity profile inside the channel on the temperature distribution is more pronounced over the low Prandtl number ones. This makes the checking of its pressure drop estimation accuracy less important, assuming the code verification is complete. With an advent of powerful computer hardware, engineering applications of computational fluid dynamics (CFD) methods have become quite common these days. Especially for a fully-turbulent and single phase convective heat transfer, the predictability of the commercial codes has matured enough so that many well-known companies adopt those to accelerate a product development cycle and to realize an increased profitability. In contrast to the above, the transition models for the CFD code are still under development, and the most of the models show limited generality and prediction accuracy. Unlike the system codes, the CFD codes estimate the pressure drop from the velocity profile which is obtained by solving momentum conservation equations, and the resulting friction factor can be a representative parameter for a constant cross section channel flow. In addition, the flow inside a rectangular channel with a high span to gap ratio can be approximated by flow inside parallel plates. The computational fluid dynamics simulation on the flow between parallel plates showed reasonable prediction capability for the laminar and the turbulent regime.

  3. Simplified Method for the Characterization of Rectangular Straw Bales (RSB) Thermal Conductivity

    Science.gov (United States)

    Conti, Leonardo; Goli, Giacomo; Monti, Massimo; Pellegrini, Paolo; Rossi, Giuseppe; Barbari, Matteo

    2017-10-01

    This research aims to design and implement tools and methods focused at the assessment of the thermal properties of full size Rectangular Straw Bales (RSB) of various nature and origin, because their thermal behaviour is one of the key topics in market development of sustainable building materials. As a first approach a method based on a Hot-Box in agreement with the ASTM C1363 - 11 standard was adopted. This method was found to be difficult for the accurate measurement of energy flows. Instead, a method based on a constant energy input was developed. With this approach the thermal conductivity of a Rectangular Straw-Bale (RSB λ) can be determined by knowing the thermal conductivity of the materials used to build the chamber and the internal and external temperature of the samples and of the chamber. A measurement a metering chamber was built and placed inside a climate chamber, maintained at constant temperature. A known quantity of energy was introduced inside the metering chamber. A series of thermopiles detects the temperature of the internal and external surfaces of the metering chamber and of the specimens allowing to calculate the thermal conductivity of RSB in its natural shape. Different cereal samples were tested. The values were found consistent with those published in scientific literature.

  4. Counter-current gas-liquid two-phase flow in a narrow rectangular channel

    International Nuclear Information System (INIS)

    Sohn, Byung Hu; Kim, Byong Joo

    2000-01-01

    A study of counter-current two-phase flow in a narrow rectangular channel has been performed. Two-phase flow patterns and void fractions were experimentally studied in a 760 mm long and 100 mm wide test section with 3.0 mm gap. The resulting data have been compared to previous transition criteria and empirical correlations. The comparison of experimental data to the transition criteria developed by Taitel and Barnea showed good agreement for the bubbly-to-slug transition. For the criteria of Mishima and Ishii to be applicable to the slug to churn transition, a new model seems to be needed for the accurate prediction of the distribution parameter for the counter-current flow in narrow rectangular channels. For the churn-to-annular transition the model of Taitel and Barnea was found to be close to the experimental data. However the model should be improved in conjunction with the channel geometry to accurately predict the counter-current flow limitation and flow transition. It was verified the distribution parameter was well-correlated by the drift-flux model. The distribution parameter for the present study was found to be about 1.2 for all flow regimes except 1.0 for an annular flow. (author)

  5. The Importance of Lower Mantle Structure to Plate Stresses and Plate Motions

    Science.gov (United States)

    Holt, W. E.; Wang, X.; Ghosh, A.

    2016-12-01

    Plate motions and plate stresses are widely assumed as the surface expression of mantle convection. The generation of plate tectonics from mantle convection has been studied for many years. Lithospheric thickening (or ridge push) and slab pull forces are commonly accepted as the major driving forces for the plate motions. However, the importance of the lower mantle to plate stresses and plate motions remains less clear. Here, we use the joint modeling of lithosphere and mantle dynamics approach of Wang et al. (2015) to compute the tractions originating from deeper mantle convection and follow the method of Ghosh et al. (2013) to calculate gravitational potential energy per unit area (GPE) based on Crust 1.0 (Laske et al., 2013). Absolute values of deviatoric stresses are determined by the body force distributions (GPE gradients and traction magnitudes applied at the base of the lithosphere). We use the same relative viscosity model that Ghosh et al. (2013) used, and we solve for one single adjustable scaling factor that multiplies the entire relative viscosity field to provide absolute values of viscosity throughout the lithosphere. This distribution of absolute values of lithosphere viscosities defines the magnitudes of surface motions. In this procedure, the dynamic model first satisfies the internal constraint of no-net-rotation of motions. The model viscosity field is then scaled by the single factor until we achieve a root mean square (RMS) minimum between computed surface motions and the kinematic no-net-rotation (NNR) model of Kreemer et al. (2006). We compute plate stresses and plate motions from recently published global tomography models (over 70 based on Wang et al., 2015). We find that RMS misfits are significantly reduced when details of lower mantle structure from the latest tomography models are added to models that contain only upper and mid-mantle density distributions. One of the key reasons is that active upwelling from the Large Low Shear

  6. Design and fabrication of a large rectangular magnetic cusp plasma source for high intensity neutral beam injectors

    International Nuclear Information System (INIS)

    Biagi, L.A.; Berkner, K.H.; Ehlers, K.W.; Paterson, J.A.; Porter, J.R.

    1979-11-01

    The design and fabrication techniques for a large, rectangular magnetic bucket plasma source are described. This source is compatible with the accelerator structures for the TFTR and DIII neutral-beam systems

  7. Oscillating-flow loss test results in rectangular heat exchanger passages

    Science.gov (United States)

    Wood, J. Gary

    1991-01-01

    Test results of oscillating flow losses in rectangular heat exchanger passages of various aspect ratios are given. This work was performed in support of the design of a free-piston Stirling engine (FPSE) for a dynamic space power conversion system. Oscillating flow loss testing was performed using an oscillating flow rig, which was based on a variable stroke and variable frequency linear drive motor. Tests were run over a range of oscillating flow parameters encompassing the flow regimes of the proposed engine design. Test results are presented in both tabular and graphical form and are compared against analytical predictions.

  8. Catalysts characteristics of Ni/YSZ core-shell according to plating conditions using electroless plating

    Science.gov (United States)

    Park, Hyun-Wook; Jang, Jae-Won; Lee, Young-Jin; Kim, Jin-Ho; Jeon, Dae-Woo; Lee, Jong-Heun; Hwang, Hae-jin; Lee, Mi-Jai

    2017-11-01

    This study aims to develop an anode catalyst for a solid oxide fuel cell (SOFC) using electroless nickel plating. We have proposed a new method for electroless plating of Ni metal on yttria-stabilized zirconia (YSZ) particles. We examine the uniformity of the Ni layer on the plated core-shell powder, in addition to the content of Ni and the reproducibility of the plating. We have also evaluated the carbon deposition rate and characteristics of the SOFC anode catalyst. To synthesize Ni-plated YSZ particles, the plated powder is heat-treated at 1200 °C. The resultant particles, which have an average size of 50 μm, were subsequently used in the experiment. The size of the Ni particles and the Ni content both increase with increasing plating temperature and plating time. The X-ray diffraction pattern reveals the growth of Ni particles. After heat-treatment, Ni is oxidized to NiO, leading to the co-existence of Ni and NiO; Ni3P is also observed due to the presence of phosphorous in the plating solution. Following heat treatment for 1 h at 1200 °C, Ni is mostly oxidized to NiO. The carbon deposition rate of the reference YSZ powder is 135%, while that of the Ni-plated YSZ is 1%-6%.

  9. The nanosecond generator RG-1 with near-rectangular pulse

    International Nuclear Information System (INIS)

    Bulan, V.V.; Grabovskij, E.V.; Gribov, A.N.; Luzhnov, V.G.

    1996-01-01

    The 300 kV, 17 Ohm generator RG-1, which can deliver near-rectangular pulses with a pulse duration of 80 ns FWHM, is described. The polarity of the output pulse can be changed by a simple switch. The fast capacities of the Marx generator are used instead of the pulse forming line. Multi-spark gas switches were developed to decrease the inductance of the discharged circuit. The generator is supplied by a built-in high voltage source and its operation is controlled by a minicomputer. It is used the power supply-line 220 V. The RG-1 can be used in different modes of operation: gas discharge, particle beam formation, etc. (author). 4 figs., 3 refs

  10. Rectangular amplitudes, conformal blocks, and applications to loop models

    Energy Technology Data Exchange (ETDEWEB)

    Bondesan, Roberto, E-mail: roberto.bondesan@cea.fr [LPTENS, Ecole Normale Superieure, 24 rue Lhomond, 75231 Paris (France); Institute de Physique Theorique, CEA Saclay, F-91191 Gif-sur-Yvette (France); Jacobsen, Jesper L. [LPTENS, Ecole Normale Superieure, 24 rue Lhomond, 75231 Paris (France); Universite Pierre et Marie Curie, 4 place Jussieu, 75252 Paris (France); Saleur, Hubert [Institute de Physique Theorique, CEA Saclay, F-91191 Gif-sur-Yvette (France); Physics Department, USC, Los Angeles, CA 90089-0484 (United States)

    2013-02-21

    In this paper we continue the investigation of partition functions of critical systems on a rectangle initiated in [R. Bondesan, et al., Nucl. Phys. B 862 (2012) 553-575]. Here we develop a general formalism of rectangle boundary states using conformal field theory, adapted to describe geometries supporting different boundary conditions. We discuss the computation of rectangular amplitudes and their modular properties, presenting explicit results for the case of free theories. In a second part of the paper we focus on applications to loop models, discussing in details lattice discretizations using both numerical and analytical calculations. These results allow to interpret geometrically conformal blocks, and as an application we derive new probability formulas for self-avoiding walks.

  11. The nanosecond generator RG-1 with near-rectangular pulse

    Energy Technology Data Exchange (ETDEWEB)

    Bulan, V V; Grabovskij, E V; Gribov, A N; Luzhnov, V G [TRINITI, Troitsk (Russian Federation)

    1997-12-31

    The 300 kV, 17 Ohm generator RG-1, which can deliver near-rectangular pulses with a pulse duration of 80 ns FWHM, is described. The polarity of the output pulse can be changed by a simple switch. The fast capacities of the Marx generator are used instead of the pulse forming line. Multi-spark gas switches were developed to decrease the inductance of the discharged circuit. The generator is supplied by a built-in high voltage source and its operation is controlled by a minicomputer. It is used the power supply-line 220 V. The RG-1 can be used in different modes of operation: gas discharge, particle beam formation, etc. (author). 4 figs., 3 refs.

  12. Counter-current flow limited CHF in thin rectangular channels

    International Nuclear Information System (INIS)

    Cheng, L.Y.

    1990-01-01

    An analytical expression for counter-current-flow-limitation (CCFL) was used to predict critical heat flux (CHF) for downward flow in thin vertical rectangular channels which are prototypes of coolant channels in test and research nuclear reactors. Top flooding is the mechanism for counter-current flow limited CHF. The CCFL correlation also was used to determine the circulation and flooding-limited CHF. Good agreements were observed between the period the model predictions and data on the CHF for downflow. The minimum CHF for downflow is lower than the flooding-limited CHF and it is predicted to occur at a liquid flow rate higher than that at the flooding limit. 17 refs., 7 figs

  13. Fuel cell end plate structure

    Science.gov (United States)

    Guthrie, Robin J.; Katz, Murray; Schroll, Craig R.

    1991-04-23

    The end plates (16) of a fuel cell stack (12) are formed of a thin membrane. Pressure plates (20) exert compressive load through insulation layers (22, 26) to the membrane. Electrical contact between the end plates (16) and electrodes (50, 58) is maintained without deleterious making and breaking of electrical contacts during thermal transients. The thin end plate (16) under compressive load will not distort with a temperature difference across its thickness. Pressure plate (20) experiences a low thermal transient because it is insulated from the cell. The impact on the end plate of any slight deflection created in the pressure plate by temperature difference is minimized by the resilient pressure pad, in the form of insulation, therebetween.

  14. Conversion of output factor from square field into rectangular field in electron beam

    CERN Document Server

    Wang Jian Hua; Xu Yi Fei

    2002-01-01

    Objective: A simple and accurate calculation method was designed to convert output factor from square field into rectangular field in electron beam, which can be easily implemented in clinical practice. Methods: 6, 12, 15 MeV electron beam, field size 6.0 cm x 7.5 cm, 5.0 cm x 10.0 cm, 6.0 cm x 12.0 cm, TL3000C dosimeter and source-to-surface distance method were used in dose measurement. The measured dose values were compared with the calculated ones from three theoretical equations with the conformation evaluated. Results: The calculated dose values from three theoretical equations differed from the measured ones by 0.23%, 1.30% and 1.10% (6 MeV), 0.63%, 0.90% and 0.73% (12 MeV), 0.50%, 1.80% and 3.40% (15 MeV), conforming best to the equation OUF (X, Y)=[OUF(X,X). OUF(Y,Y)] sup 1 sup / sup 2. When the size of the field was longer than Rp, the difference between the calculated values and measured ones was relatively very small. Conclusions: The output factor in rectangular fields can be accurately calculate...

  15. Heat insulating plates

    Energy Technology Data Exchange (ETDEWEB)

    Allan, J.A.F.

    1976-10-28

    Micro-porous insulation plates are dealt with, for example, how they are used in the insulation of heat storage devices. Since one side of such plates is exposed to a temperature of over 700/sup 0/C, a shrinkage of the glass texture of the covering can occur, which can exceed the shrinkage of the inner micro-porous material, so that cracks and splits in the high temperature side of the covering can come about. The task of the invention is to design the plate in such a way as to prevent this from happening. For this purpose the plate is provided, according to invention specifications, with flutes, waves, ribs, waffle or grid patterns and the covering is set into the recesses originating from this.

  16. Stresses and Displacements in Functionally Graded Materials of Semi-Infinite Extent Induced by Rectangular Loadings

    Directory of Open Access Journals (Sweden)

    Zhong-Qi Yue

    2012-01-01

    Full Text Available This paper presents the stress and displacement fields in a functionally graded material (FGM caused by a load. The FGM is a graded material of Si3N4-based ceramics and is assumed to be of semi-infinite extent. The load is a distributed loading over a rectangular area that is parallel to the external surface of the FGM and either on its external surface or within its interior space. The point-load analytical solutions or so-called Yue’s solutions are used for the numerical integration over the distributed loaded area. The loaded area is discretized into 200 small equal-sized rectangular elements. The numerical integration is carried out with the regular Gaussian quadrature. Weak and strong singular integrations encountered when the field points are located on the loaded plane, are resolved with the classical methods in boundary element analysis. The numerical integration results have high accuracy.

  17. The testing of the Rectangular Pivot-point bellows for the PPPL Tokamak fusion test reactor

    International Nuclear Information System (INIS)

    Haughian, J.; Fong, M.; Greer, J.; Lou, K.; Scalise, D.T.

    1983-01-01

    The Neutral Beam Pivot Point Bellows (PPB) is installed in the duct which connects the Neutral Beam Enclosure to the Torus. This bellows, located at the pivot point, must fit the severely limited space available at the pivot-point location. Consequently, it has to be made rectangular in cross section with a large inside area for beam access. This leads to small convolutions with high stress concentrations. The function of the bellows is to permit change in the angular positioning of the neutral beam line with respect to the Tokamak, to isolate the Neutral Beam Line from the deflection of the Torus during bake out, and to allow for all misalignments. Internally the bellows will have a vacuum along with such gases such as hydrogen or deuterium. Externally, air or nitrogen gas will be present. It is constructed of Inconel 718 convolutions welded together to provide a clear rectangular opening of 23.4 by 32.2 inches, joined to a 625 Inconel flange at each end

  18. Fuel cell cooler-humidifier plate

    Science.gov (United States)

    Vitale, Nicholas G.; Jones, Daniel O.

    2000-01-01

    A cooler-humidifier plate for use in a proton exchange membrane (PEM) fuel cell stack assembly is provided. The cooler-humidifier plate combines functions of cooling and humidification within the fuel cell stack assembly, thereby providing a more compact structure, simpler manifolding, and reduced reject heat from the fuel cell. Coolant on the cooler side of the plate removes heat generated within the fuel cell assembly. Heat is also removed by the humidifier side of the plate for use in evaporating the humidification water. On the humidifier side of the plate, evaporating water humidifies reactant gas flowing over a moistened wick. After exiting the humidifier side of the plate, humidified reactant gas provides needed moisture to the proton exchange membranes used in the fuel cell stack assembly. The invention also provides a fuel cell plate that maximizes structural support within the fuel cell by ensuring that the ribs that form the boundaries of channels on one side of the plate have ends at locations that substantially correspond to the locations of ribs on the opposite side of the plate.

  19. Three-dimensional flat shell-to-shell coupling: numerical challenges

    Science.gov (United States)

    Guo, Kuo; Haikal, Ghadir

    2017-11-01

    The node-to-surface formulation is widely used in contact simulations with finite elements because it is relatively easy to implement using different types of element discretizations. This approach, however, has a number of well-known drawbacks, including locking due to over-constraint when this formulation is used as a twopass method. Most studies on the node-to-surface contact formulation, however, have been conducted using solid elements and little has been done to investigate the effectiveness of this approach for beam or shell elements. In this paper we show that locking can also be observed with the node-to-surface contact formulation when applied to plate and flat shell elements even with a singlepass implementation with distinct master/slave designations, which is the standard solution to locking with solid elements. In our study, we use the quadrilateral four node flat shell element for thin (Kirchhoff-Love) plate and thick (Reissner-Mindlin) plate theory, both in their standard forms and with improved formulations such as the linked interpolation [1] and the Discrete Kirchhoff [2] elements for thick and thin plates, respectively. The Lagrange multiplier method is used to enforce the node-to-surface constraints for all elements. The results show clear locking when compared to those obtained using a conforming mesh configuration.

  20. Three-dimensional flat shell-to-shell coupling: numerical challenges

    Directory of Open Access Journals (Sweden)

    Guo Kuo

    2017-11-01

    Full Text Available The node-to-surface formulation is widely used in contact simulations with finite elements because it is relatively easy to implement using different types of element discretizations. This approach, however, has a number of well-known drawbacks, including locking due to over-constraint when this formulation is used as a twopass method. Most studies on the node-to-surface contact formulation, however, have been conducted using solid elements and little has been done to investigate the effectiveness of this approach for beam or shell elements. In this paper we show that locking can also be observed with the node-to-surface contact formulation when applied to plate and flat shell elements even with a singlepass implementation with distinct master/slave designations, which is the standard solution to locking with solid elements. In our study, we use the quadrilateral four node flat shell element for thin (Kirchhoff-Love plate and thick (Reissner-Mindlin plate theory, both in their standard forms and with improved formulations such as the linked interpolation [1] and the Discrete Kirchhoff [2] elements for thick and thin plates, respectively. The Lagrange multiplier method is used to enforce the node-to-surface constraints for all elements. The results show clear locking when compared to those obtained using a conforming mesh configuration.

  1. Theroretical modelling of the plate-tubes coupling in the hydroelasticity of the perforated plates

    International Nuclear Information System (INIS)

    Dzhupanov, V.A.; Manoach, E.S.

    1983-01-01

    In the previous investigations on the perforated plate hydroelasticity the problem of the plates-tubes-liquid interaction in the process of the general structural vibration is stated. But the interaction of the vibrating plates with the tubes, passing through them, is taken into account considering the tubes only as absolutely rigid supports. This is one of the possible technical realizations. In the present article the case when the tubes are taking part in the plate motion (vibration) is studied. Two circular perforated plates are supported by the absolutely rigid wall of the modelled roundcircular reactor barrel. The distance between the plates is given. They are connected by tubes, passing through, and clamped into the perforation holes. The plates and the tubes are made by any elastic HOOKIAN material. The volume between the two plates and outwardly to the tubes, but intrinsically of the barrel is filled by ideal, compressible and heavy liquid. Evidently the liquid volume is multiconnected one. The free vibration of the whole system is considered with the purposes: i) to give a theoretical model of the plates-tubes-liquid interaction including governing equations and boundary conditions; ii) to trace the solution of the eigen-value problem for the modelled structure; iii) to underline the engineering sides of the modelling process. (orig./GL)

  2. Total reflection and cloaking by zero index metamaterials loaded with rectangular dielectric defects

    KAUST Repository

    Wu, Ying

    2013-05-06

    In this work, we investigate wave transmission property through a zero index metamaterial (ZIM) waveguide embedded with rectangular dielectric defects. We show that total reflection and total transmission (cloaking) can be achieved by adjusting the geometric sizes and/or permittivities of the defects. Our work provides another possibility of manipulating wave propagation through ZIM in addition to the widely studied dielectric defects with cylindrical geometries.

  3. Total reflection and cloaking by zero index metamaterials loaded with rectangular dielectric defects

    KAUST Repository

    Wu, Ying; Li, Jichun

    2013-01-01

    In this work, we investigate wave transmission property through a zero index metamaterial (ZIM) waveguide embedded with rectangular dielectric defects. We show that total reflection and total transmission (cloaking) can be achieved by adjusting the geometric sizes and/or permittivities of the defects. Our work provides another possibility of manipulating wave propagation through ZIM in addition to the widely studied dielectric defects with cylindrical geometries.

  4. Modeling of parallel-plate regenerators with non-uniform plate distributions

    DEFF Research Database (Denmark)

    Jensen, Jesper Buch; Engelbrecht, Kurt; Bahl, Christian Robert Haffenden

    2010-01-01

    plate spacing distributions are presented in order to understand the impact of spacing non-uniformity. Simulations of more realistic distributions where the plate spacings follow normal distributions are then discussed in order to describe the deviation of the performance of a regenerator relative...

  5. Highly conductive composites for fuel cell flow field plates and bipolar plates

    Science.gov (United States)

    Jang, Bor Z; Zhamu, Aruna; Song, Lulu

    2014-10-21

    This invention provides a fuel cell flow field plate or bipolar plate having flow channels on faces of the plate, comprising an electrically conductive polymer composite. The composite is composed of (A) at least 50% by weight of a conductive filler, comprising at least 5% by weight reinforcement fibers, expanded graphite platelets, graphitic nano-fibers, and/or carbon nano-tubes; (B) polymer matrix material at 1 to 49.9% by weight; and (C) a polymer binder at 0.1 to 10% by weight; wherein the sum of the conductive filler weight %, polymer matrix weight % and polymer binder weight % equals 100% and the bulk electrical conductivity of the flow field or bipolar plate is at least 100 S/cm. The invention also provides a continuous process for cost-effective mass production of the conductive composite-based flow field or bipolar plate.

  6. Discharge Coefficient of Rectangular Short-Crested Weir with Varying Slope Coefficients

    Directory of Open Access Journals (Sweden)

    Yuejun Chen

    2018-02-01

    Full Text Available Rectangular short-crested weirs are widely used for simple structure and high discharge capacity. As one of the most important and influential factors of discharge capacity, side slope can improve the hydraulic characteristics of weirs at special conditions. In order to systemically study the effects of upstream and downstream slope coefficients S1 and S2 on overflow discharge coefficient in a rectangular short-crested weir the Volume of Fluid (VOF method and the Renormalization Group (RNG κ-ε turbulence model are used. In this study, the slope coefficient ranges from V to 3H:1V and each model corresponds to five total energy heads of H0 ranging from 8.0 to 24.0 cm. Comparisons of discharge coefficients and free surface profiles between simulated and laboratory results display a good agreement. The simulated results show that the difference of discharge coefficients will decrease with upstream slopes and increase with downstream slopes as H0 increases. For a given H0, the discharge coefficient has a convex parabolic relation with S1 and a piecewise linearity relation with S2. The maximum discharge coefficient is always obtained at S2 = 0.8. There exists a difference between upstream and downstream slope coefficients in the influence range of free surface curvatures. Furthermore, a proposed discharge coefficient equation by nonlinear regression is a function of upstream and downstream slope coefficients.

  7. Phase distribution measurements in narrow rectangular channels using image processing techniques

    International Nuclear Information System (INIS)

    Bentley, C.; Ruggles, A.

    1991-01-01

    Many high flux research reactor fuel assemblies are cooled by systems of parallel narrow rectangular channels. The HFIR is cooled by single phase forced convection under normal operating conditions. However, two-phase forced convection or two phase mixed convection can occur in the fueled region as a result of some hypothetical accidents. Such flow conditions would occur only at decay power levels. The system pressure would be around 0.15 MPa in such circumstances. Phase distribution of air-water flow in a narrow rectangular channel is examined using image processing techniques. Ink is added to the water and clear channel walls are used to allow high speed still photographs and video tape to be taken of the air-water flow field. Flow field images are digitized and stored in a Macintosh 2ci computer using a frame grabber board. Local grey levels are related to liquid thickness in the flow channel using a calibration fixture. Image processing shareware is used to calculate the spatially averaged liquid thickness from the image of the flow field. Time averaged spatial liquid distributions are calculated using image calculation algorithms. The spatially averaged liquid distribution is calculated from the time averaged spatial liquid distribution to formulate the combined temporally and spatially averaged fraction values. The temporally and spatially averaged liquid fractions measured using this technique compare well to those predicted from pressure gradient measurements at zero superficial liquid velocity

  8. Ni-based amorphous alloy-coating for bipolar plate of PEM fuel cell by electrochemical plating

    International Nuclear Information System (INIS)

    Yamaura, S; Kim, S C; Inoue, A

    2013-01-01

    In this study, the Ni-Cr-P amorphous alloy-coated bipolar plates were produced by electro-plating on the Cu base plates with a flow field. The power generation tests of a single fuel cell with those Ni-Cr-P bipolar plates were conducted at 353 K. It was found that the single fuel cell with those Ni-Cr-P bipolar plates showed excellent I-V performance as well as that with the carbon graphite bipolar plates. It was also found that the single cell with those Ni-Cr-P bipolar plates showed better I-V performance than that with the Ni-P amorphous alloy-coated bipolar plates. Furthermore, the long-time operation test was conducted for 440 h with those Ni-Cr-P bipolar plates at the constant current density of 200 mA·cm −2 . As a result, it was found that the cell voltage gradually decreased at the beginning of the measurement before 300 h and then the voltage was kept constant after 300 h.

  9. ABOUT INFLUENCE OF DIFFERENT SCHEMES IMPACT RADIATION ENVIRONMENTS AND LOADS ON REINFORCED LAMELLAR STRUCTURAL MEMBERS

    Directory of Open Access Journals (Sweden)

    Rafail B. Garibov

    2017-12-01

    Full Text Available The article discusses the model of deformation of fiber-reinforced concrete rectangular plate under the influence of radiation environments. In the calculation of the plate was considered different schemes impact of the applied external loads and radiation environments.

  10. Numerical Simulation of Passage of a Neutrophil through a Rectangular Channel with a Moderate Constriction

    Science.gov (United States)

    Shirai, Atsushi; Masuda, Sunao

    2013-01-01

    The authors have previously presented a mathematical model to predict transit time of a neutrophil through an alveolar capillary segment which was modeled as an axisymmetric arc-shaped constriction settled in a cylindrical straight pipe to investigate the influence of entrance curvature of a capillary on passage of the cell. The axially asymmetric cross section of a capillary also influences the transit time because it requires three-dimensional deformation of a cell when it passes through the capillary and could lead to plasma leakage between the cell surface and the capillary wall. In this study, a rectangular channel was introduced, the side walls of which were moderately constricted, as a representative of axially asymmetric capillaries. Dependence of transit time of a neutrophil passing through the constriction on the constriction geometry, i.e., channel height, throat width and curvature radius of the constriction, was numerically investigated, the transit time being compared with that through the axisymmetric model. It was found that the transit time is dominated by the throat hydraulic diameter and curvature radius of the constriction and that the throat aspect ratio little affects the transit time with a certain limitation, indicating that if an appropriate curvature radius is chosen, such a rectangular channel model can be substituted for an axisymmetric capillary model having the same throat hydraulic diameter in terms of the transit time by choosing an appropriate curvature radius. Thus, microchannels fabricated by the photolithography technique, whose cross section is generally rectangular, are expected to be applicable to in vitro model experiments of neutrophil retention and passage in the alveolar capillaries. PMID:23527190

  11. Theory of the special Smith-Purcell radiation from a rectangular grating

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Weihao, E-mail: liuwhao@ustc.edu.cn; He, Zhigang, E-mail: hezhg@ustc.edu.cn; Jia, Qika [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui, 230029 (China); Li, Weiwei [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei, Anhui, 230029 (China); Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati, via E. Fermi 40, 00044 Frascati, RM (Italy)

    2015-12-15

    The recently uncovered special Smith-Purcell radiation (S-SPR) from the rectangular grating has significantly higher intensity than the ordinary Smith-Purcell radiation (SPR). Its monochromaticity and directivity are also much better. Here we explored the mechanism of the S-SPR by applying the fundamental electromagnetic theory and simulations. We have confirmed that the S-SPR is exactly from the radiating eigen modes of the grating. Its frequency and direction are well correlated with the beam velocity and structure parameters, which indicates its promising applications in tunable wave generation and beam diagnostic.

  12. Experimental study on downward two-phase flow in narrow rectangular channel

    Energy Technology Data Exchange (ETDEWEB)

    Kim, T.H.; Jeong, J.H. [Pusan National Univ., Busan (Korea, Republic of)

    2014-07-01

    Adiabatic vertical two-phase flow of air and water through narrow rectangular channels was investigated. This study involved the observation of flow using a high speed camera and flow regimes were determined by image processing program using a MATLAB. The flows regimes in channel with downward flow are similar to those found by previous studies with upward flow. The flow regimes in downward flow at low liquid velocity are different from the previous studies in upward flow. The flow regimes can be classified into bubbly, cap-bubbly, slug and churn flow. (author)

  13. LUGS, Stress Analysis, Flexibility Factors for Rectangular Attachment on Thin Shell

    International Nuclear Information System (INIS)

    Dodge, W.G.

    1977-01-01

    1 - Description of problem or function: LUGS calculates stresses, stress indices, and flexibility factors for a rectangular attachment on a cylindrical shell. 2 - Method of solution: The program implements Bijlaard's series solution to the thin-shell equations. 3 - Restrictions on the complexity of the problem: Caution is recommended in using the code for attachments on very thin shells that have large circumferential dimension and small longitudinal dimension (GAMMA.GE.80, BETA2.LE.0.05, and BETA1.GE.0.3) as series convergence and/or numeric problems seem to exist

  14. Theory of the special Smith-Purcell radiation from a rectangular grating

    International Nuclear Information System (INIS)

    Liu, Weihao; He, Zhigang; Jia, Qika; Li, Weiwei

    2015-01-01

    The recently uncovered special Smith-Purcell radiation (S-SPR) from the rectangular grating has significantly higher intensity than the ordinary Smith-Purcell radiation (SPR). Its monochromaticity and directivity are also much better. Here we explored the mechanism of the S-SPR by applying the fundamental electromagnetic theory and simulations. We have confirmed that the S-SPR is exactly from the radiating eigen modes of the grating. Its frequency and direction are well correlated with the beam velocity and structure parameters, which indicates its promising applications in tunable wave generation and beam diagnostic

  15. Specific aspects of turbulent flow in rectangular ducts

    Directory of Open Access Journals (Sweden)

    Stanković Branislav D.

    2017-01-01

    Full Text Available The essential ideas of investigations of turbulent flow in a straight rectangular duct are chronologically presented. Fundamentally significant experimental and theoretical studies for mathematical modeling and numerical computations of this flow configuration are analyzed. An important physical aspect of this type of flow is presence of secondary motion in the plane perpendicular to the streamwise direction, which is of interest from both the engineering and the scientific viewpoints. The key facts for a task of turbulence modeling and optimal choice of the turbulence model are obtained through careful examination of physical mechanisms that generate secondary flows. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no.TR-33018: Increase in Energy and Ecology Efficiency of Processes in Pulverized Coal-Fired Furnace and Optimization of Utility Steam Boiler Air Pre-heater by Using In-House Developed Software Tools

  16. Create Your Plate

    Medline Plus

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  17. Create Your Plate

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