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  • 1980-1984  (5,695)
  • Analytical Chemistry and Spectroscopy  (4,318)
  • Engineering General  (1,377)
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  • 1
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 4 (1984) 
    ISSN: 0271-2091
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 4 (1984), S. 1-12 
    ISSN: 0271-2091
    Keywords: Review ; Finite Elements ; Meteorology ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The application of the finite-element method to the simulation of meterological fluid flow problems is reviewed. Early studies were aimed primarily at demonstrating the viability of the method for one- and two-dimensional flows, whereas more recent studies have been aimed at demonstrating the efficiency and viability of the method for more complex three-dimensional simulations. There has also been a shift towards exploiting such models to better understand and predict the underlying meteorological phenomena, rather than restricting attention to the development of the algorithms.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 4 (1984), S. 105-105 
    ISSN: 0271-2091
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 4 (1984), S. 147-158 
    ISSN: 0271-2091
    Keywords: Finite Element ; Incompressible Flow ; Pressure-specification-point ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The discontinuity of a finite-element pressure field that is sometimes present in the neighbourhood of the pressure-specification-point is shown to arise either from round-off, or from mistakes in modelling. The implications of this are considered. In particular it restricts grid refinement near the pressure-specification-point. The analysis can be extended to finite-difference calculations, and to other fields governed by equations similar to Poisson's equation.
    Additional Material: 6 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 4 (1984), S. 109-125 
    ISSN: 0271-2091
    Keywords: Finite elements ; Navier-Stokes ; Vorticity-stream function ; Time-dependent ; flows ; Boundary conditions ; Incompressible viscous flows ; Two-dimensional flows ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A new finite element method for solving the time-dependent incompressible Navier-Stokes equations with general boundary conditions is presented. The two second-order partial differential equations for the vorticity and the stream function are factorized, apart from the non-linear advection term, by eliminating the coupling due to the double specification on the stream function at (a part of) the boundary. This is achieved by reducing the no-slip boundary conditions to projection integral conditions for the vorticity field and by evaluating the relevant quantities involved according to an extension of the method of Glowinski and Pironneau for the biharmonic problem. Time integration schemes and iterative algorithms are introduced which require the solution only of banded linear systems of symmetric type. The proposed finite element formulation is compared with its finite difference equivalent by means of a few numerical examples. The results obtained using 4-noded bilinear elements provide an illustration of the superiority of the finite element based spatial discretization.
    Additional Material: 7 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 4 (1984) 
    ISSN: 0271-2091
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 0271-2091
    Keywords: Polymer Flows ; Non-Newtonian ; Moving Boundary ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Recent progress in the simulation of polymeric flows of two key problems in the injection moulding process, carried out by a team at Cornell University, is briefly described. For the filling of cooled thin cavities, the fluid is characterized by a power-law viscosity with exponential temperature dependence, and interaction between the transient thermal boundary-layer and the core flow in a domain with moving boundary is essential. The earlier procedure of Hieber and Shen is modified in two aspects: a boundary-integral formulation replaces the finite-element treatment of the pressure, and an ‘energy integral’ approach is used for the transient temperature. The second problem is the steady visco-elastic flow in the juncture region where sudden changes of the geometry and large strain rates occur. The constitutive equation is postulated according to the Leonov model. The main features in the numerical implementation are: integration along a streamline to determine the elastic deformation tensors for a given velocity field, and finite-element treatment (in time-dependent form) of the pressure and fields for given stresses. In an example where the contraction ratio is 7:1, results for nominal Deborah number exceeding 100 show no numerical instability. (However, for this problem, the true Weissenberg number, i.e. the ratio of local first-normal-stress difference to shear stress turns out to be generally O(10).) The predictions also correlate very well with experimental birefringence measurements.
    Additional Material: 9 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 4 (1984), S. 303-319 
    ISSN: 0271-2091
    Keywords: Finite Element ; Turbulent Flow ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Although the finite-element (FE) method has been successful in analysing complex laminar flows, a number of difficulties can arise when two-equation turbulence models (e.g. the k-∊ model) are incorporated. This work describes a particular FE discretization of the k-∊ model and reports its performance in recirculating flow. Severe problems encountered in attempts to obtain convergence of the numerical scheme are isolated and analysed, and methods by which the problems can be overcome are suggested.Insight gained in this work has enabled a practical turbulent flow FE code to be constructed which is robust and efficient. This code is the subject of a further paper.
    Additional Material: 8 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 4 (1984), S. 321-336 
    ISSN: 0271-2091
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Incorporation of the k-∊ turbulence model into Galerkin finite-element fluid-flow codes (which, unlike upwind finite-difference codes, have no artificial damping) can lead to severe iterative convergence difficulties. This paper introduces an alternative turbulence model (the q-f model) and an associated finite-element discretization method which are designed to overcome these problems. The new model forms the basis of a finite-element fluid-flow code which is robust and efficient. Furthermore, it is demonstrated on a practical example that the code can give good agreement with experiment on fairly coarse meshes.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 4 (1984), S. 399-419 
    ISSN: 0271-2091
    Keywords: Laminar Boundary Layers ; Finite Element Method ; Finite Difference Method ; Spectral Method Convergence ; Computational Efficiency ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The Dorodnitsyn boundary later formulation is given a finite element interpretation and found to generate very accurate and economical solutions when combined with an implicit, non-iterative marching scheme in the downstream direction. The algorithm is of order (Δ2u, Δx) whether linear or quadratic elements are used across the boundary layer. Solutions are compared with a Dorodnitsyn spectral formulation and a conventional finite difference formulation for three Falkner-Skan pressure gradient cases and the flow over a circular cylinder. With quadratic elements the Dorodnitsyn finite element formulation is approximately five times more efficient than the conventional finite difference formulation.
    Additional Material: 12 Ill.
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  • 11
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 4 (1984), S. 421-439 
    ISSN: 0271-2091
    Keywords: Laminar Flow ; Turbulent Flow ; Compressible Flow ; Separation ; Time-split Method ; Finite Element Method ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The time-split finite element method is extended to compute laminar and turbulent flows with and without separation. The examples considered are the flows past trailing edges of a flat plate and a backward-facing step. Eddy viscosity models are used to represent effects of turbulence. It is found that the time-split method produces results in agreement with previous experimental and computational results. The eddy viscosity models employed are found to give accurate predictions in all regions of flow except downstream of reattachment.
    Additional Material: 15 Ill.
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  • 12
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 4 (1984), S. 441-457 
    ISSN: 0271-2091
    Keywords: Finite Element Method ; Dip Coating ; Newtonian Fluid ; Free Surface ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A finite element simulation of the dip coating process based on a discretization of the continuum with discontinuous pressure elements is presented. The algorithm computes the flow field from natural boundary conditions while an extra condition provided by the existence of free surface is employed to displace the meniscus location towards the actual position. The process is iterative and uses a pseudo-time stepping technique coupled to a cubic spline fitting of the free surface. Numerical predictions exhibit good agreement with experimental data for Newtonian fluids in the case of flat plate dip coating as well as in the case of wire dip coating.
    Additional Material: 14 Ill.
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  • 13
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 4 (1984), S. 459-475 
    ISSN: 0271-2091
    Keywords: Augmented Lagrangian ; Finite Element Method ; Dip Coating ; Non-Newtonian Fluids ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: We apply in this paper the augmented Lagrangian method to the study of various non-Newtonian fluid flow problems, and in particular the dip coating process. We only present in this second part the treatment specific to the non-linearities involved in the constitutive equations, the first part having largely been concerned with the general description of the approximation used.Two rheological models illustrating different rheological behaviours are used to simulate dip coating process: the Carreau-A model for shear-thinning properties of the viscosity and a truncated second-order model for a Newtonian behaviour in viscosity with elastic properties.Numerical predictions show a very good agreement with experimental data for the second-order model. The discrepancy observed in the other case can be explained qualitatively by the elastic properties exhibited by the shear-thinning fluids used: this elasticity is not taken into account in the Carreau-A model.
    Additional Material: 12 Ill.
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  • 14
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 4 (1984), S. 667-683 
    ISSN: 0271-2091
    Keywords: Rotating Flow ; Finite Differences ; Numerical Stability ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A computer program has been developed to predict laminar source-sink flow in a rotating cylindrical cavity. Although the program is based on a standard finite difference technique for recirculating flow, it incorporates two novel features. Step changes in grid size are employed to obtain sufficient resolution in the boundary layers and special treatment is given to the solution of the pressure correction equations, in the ‘SIMPLE’ algorithm, in order to improve the convergence properties of the method. Results are presented both for the flow in an infinite rotating cylindrical annulus and a finite rotating cylindrical cavity, with the inner cylindrical surface acting as a uniform source and the outer cylinder as a sink. These show good agreement with existing analytical solutions and illustrate some of the problems associated with the computation of rapidly rotating flows.
    Additional Material: 8 Ill.
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  • 15
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 4 (1984), S. 685-699 
    ISSN: 0271-2091
    Keywords: Stokes Flows ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A family of simple Stokes flows involving sliding surfaces adjacent to surfaces at rest is considered. Principally, two specific flow configurations are investigated: (i) that arising when parts of the boundary of an infinitely long circular cylinder are rotating about the axis while other parts of the boundary are at rest, and (ii) the flow produced when a cap of a sphere is held at rest while the remainder of the sphere rotates about the symmetry axis. In each case computer plots of streamlines or constant velocity lines are presented to give a general impression of the resulting flow pattern.
    Additional Material: 10 Ill.
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  • 16
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 4 (1984), S. 708-708 
    ISSN: 0271-2091
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 17
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 4 (1984), S. 709-709 
    ISSN: 0271-2091
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 18
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 4 (1984), S. 765-780 
    ISSN: 0271-2091
    Keywords: Diffraction ; Hydrodynamics ; Ocean Engineering ; Underwater Structures ; Wave Forces ; Offshore Structures ; Velocity Potential ; Boundary Elements ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The fluid forces resulting from wave interaction with large submerged structures may be calculated using numerical procedures based on the solution of the associated boundary-value problem. In this paper, the analysis of wave interaction with a fixed submerged object of arbitrary cross-section and infinite length using a two-dimensional boundary value formation based on linear diffraction theory is summarized. Subsequently, the application of the boundary element method to obtain a solution is presented. The numerical considerations are emphasized with particular reference to computational efficiency.Numerical results are presented in the form of dimensionless wave force plots for various structural shapes. In the case of a bottom-seated half cylinder, for which there exists a closed-form solution, comparisons are made between results generated using both boundary element and equivalent finite element approaches. In the case of a submerged cylinder, comparisons are made between boundary element derived values and experimental results. The boundary element results compare well with both the closed-form solution and the experimental values.
    Additional Material: 14 Ill.
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  • 19
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 4 (1984) 
    ISSN: 0271-2091
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 20
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 4 (1984), S. 931-947 
    ISSN: 0271-2091
    Keywords: Two-layer Flow ; Two-step Scheme ; Selective Lumping Method ; Ishikari Bay ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A finite element method for the analysis of two-layer density flows is presented in this paper. The standard Galerkin method based on linear interpolation functions is used to yield discrete spatial variables. For numerical integration in time, an explicit two-step selective lumping method is used. Here it is applied to a flow analysis of Ishikari Bay, at the mouth of Ishikari River. This case demonstrates a procedure that yields a numerically stable solution.
    Additional Material: 15 Ill.
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  • 21
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 4 (1984), S. 949-969 
    ISSN: 0271-2091
    Keywords: Navier-Stokes ; Discrete Fourier Transform ; Finite Difference ; Short Convolutions ; No-slip Boundary Condition ; Far Field Condition ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A mixed discrete Fourier transform-Finite difference algorithm is developed and used for the calculation of rapidly changing viscous fluid flows past a circular cylinder. The numerical approach has been designed to overcome certain difficulties arising for high Reynolds number simulations. The foremost advantage of the technique lies in its fast calculations of the convolution sums portraying the convective terms of the governing equations. Third-order spatial discretizations and fourth-order time marching are implemented.New schemes are proposed for the boundary conditions at the solid wall and at large distances. The techniques are tested on a case study with other schemes (summarized by Roache1) in order to obtain an optimal choice. Definite indications on the stability and accuracy of boundary condition schemes are achieved. Support for the statement of dominant importance of boundary conditions is also given.A comparison of computational results with experimental data is presented for the case study of the flow past an impulsively started cylinder at Reynolds number 20.The time development of the symmetrical zone of recirculation, which is formed at an early stage of the flow, has been studied for 300 ≤ Re ≤ 9500 by means of the proposed algorithm. Computational results, comparisons with experimental data2 and discussion of upper limits of validity of the procedure will be presented in a companion paper.
    Additional Material: 8 Ill.
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  • 22
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 4 (1984), S. 997-998 
    ISSN: 0271-2091
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 23
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 4 (1984), S. 999-999 
    ISSN: 0271-2091
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 24
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 4 (1984), S. 989-996 
    ISSN: 0271-2091
    Keywords: Galerkin ; Spline ; Stability ; Disk ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The perturbation equations which characterize the stability of flow over a rotating infinite disk are derived via strict order of magnitude analysis. These equations contain viscous terms not considered by Stuart,1 curvature and Coriolis terms not considered by Brown,2 and axial velocity terms not considered by Kobayashi et al.3 The strategy for reducing the problem to an algebraic system is Galerkin's method with B-spline discretization. In comparison with the Poiseuille flow solutions of Orszag,4 the method is shown to perform well without placing undue demands on computing capability. Critical values of Reynolds number, wave length, vortex orientation and number of spiral vortices calculated by the present method compare favourably with experimental data of Kobayashi et al.
    Additional Material: 4 Ill.
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  • 25
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 4 (1984), S. 1001-1012 
    ISSN: 0271-2091
    Keywords: Compressible Fluid Flow ; Numerical Analysis ; Pressure Method ; von Kármán Vortex Street ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: In this paper the pressure method for incompressible fluid flow simulation is extended and applied to the numerical simulation of compressible fluid flow. The governing equations, obtained from the physical principles of conservation of momentum, mass and energy, are first studied from a characteristic point of view. Then they are discretized with a semi-implicit finite difference technique in such a fashion that stability is achieved independently of the speed of sound. The resulting algorithm is fast, accurate and particularly efficient in subsonic flow calculations. As an example, the computer simulation of the von Kármán vortex street is described and discussed.
    Additional Material: 7 Ill.
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  • 26
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Mass Spectrometry Reviews 3 (1984), S. 1-37 
    ISSN: 0277-7037
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 13 Ill.
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  • 27
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Mass Spectrometry Reviews 3 (1984), S. 153-154 
    ISSN: 0277-7037
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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  • 28
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Mass Spectrometry Reviews 3 (1984), S. 155-155 
    ISSN: 0277-7037
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
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  • 29
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Mass Spectrometry Reviews 3 (1984) 
    ISSN: 0277-7037
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 30
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Mass Spectrometry Reviews 3 (1984), S. 591-593 
    ISSN: 0277-7037
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 31
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Mass Spectrometry Reviews 3 (1984), S. 587-587 
    ISSN: 0277-7037
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 32
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    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 11 (1984) 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 33
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    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 11 (1984), S. 1-3 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A simple, high throughput method of analysis of trimethylamine in body fluids has been developed to assist with the management of patients with the inherited metabolic disorder, trimethylaminuria. The headspace in sealed vials was analysed using perdeuterated (2H10)trimethylamine hydrochloride as an internal standard. The gas chromatograph inlet system of the mass spectrometer was adapted to suit this method of analysis. Medium resolving power was used to measure the ion ratio of the [M-H]+ ion of trimethylamine and the [M-2H]+ ion of the internal standard. The method is faster and more accurate than gas chromatographic methods. The concentrations of trimethylamine found in normal urine are similar to those reported previously.
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  • 34
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    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 11 (1984), S. 4-9 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The direct analysis of underivatized steroid and vitamin D glucuronide and sulfate conjugates by positive and negative ion fast atom bombardment mass spectrometry has been demonstrated. The technique allows unambiguous molecular weight determination of these conjugates and provides useful fragmentation information in many cases. Analysis of low microgram amounts of such conjugates purified from biological sources has been carried out.
    Additional Material: 8 Ill.
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  • 35
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Positive ion and negative ion fast atom bombardment mass spectra of several natural and synthetic enzyme inhibitors are presented. It is shown that the fast atom bombardment method is well suited to the analysis of these unusual peptides. Complete amino acid sequences can be deduced from the mass spectra in most cases. Structural features typical of the inhibitors include (a) C-terminal aldehyde groups (e.g. leupeptin), (b) urea linkages in the peptide backbone (e.g. antipain, chymostatin), (c) prevalence of arginyl or α-(2-iminohexahydropyrimidyl)glycl residues, and (d) presence of an N-(glycosylphosphoryl) group (e.g. phosphoramidon). Several examples of synthetic peptides with common protecting groups are also presented. It is concluded that positive ion and negative ion fast atom bombardment mass spectra provide complementary information, the two techniques being sensitive to entirely different structural aspects of the inhibitors.
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  • 36
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Quantification of 2-ketoglutaric acid in plasma and cerebrospinal fluid as its O-trimethylsilyl-quinoxalinol derivative by gas chromatography chemical ionization mass spectrometry is described with benzoylformic acid as internal standard. This technique, with ammonia as reactant gas, only detects the protonated molecular ions. The recovery of 2-ketoglutarate from perchloric-deproteinized plasmas is 99.7±1.2%. The normal value of 2-ketoglutarate in children is 8.6±2.6 μmol I-1 (Mean ± standard deviation) in plasma (n =25) and 4.8±1.4 μmol I-1 in cerebrospinal fluid (n 20). The plasma level of 2-ketoglutarte is correlated with urea concentration (r = 0.96; p 〈 0.001) in healthy subjects and in patients with chronic renal insufficiency. Increased values are found in one case of pyruvate carboxylase deficiency, and inconstantly in diabetes; physiological variations are described during tasting and after an oral glucose load.
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  • 37
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    Biological Mass Spectrometry 11 (1984), S. 41-46 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The positive and negative fast atom bombardment spectra of two nucleosides, 10 mononucleotides, two derivatized mononucleotides and 11 dinucleoside monophosphates have been recorded. Molecular ions (protonated or deprotonated) and some structurally significant fragments, sometimes involving cationization, were obtained. The spectra were compared with field desorption and thermospray ionization spectra whenever possible.
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  • 38
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    Biological Mass Spectrometry 11 (1984), S. 35-40 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Field desorption mass spectral data relative to 38 anthracycline derivatives are presented. A molecular ion, or [MH]+ ion is always present; in most cases it is the base peak in the spectrum at the best anode temperature. Increase in the emitter temperature promotes fragmentation which gives useful structural information. A comparison has been made between field desorption and other soft ionization techniques such as fast atom bombardment, desorption chemical ionization and a liquid chromatographic mass spectrometric interface with direct liquid introduction into a chemical ionization ion source. The most significant results were obtained by using positive and negative ion fast atom bombardment and direct liquid introduction with negative ion detection.
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  • 39
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Betaxolol, a beta selective adrenoceptor antagonist recently approved for the treatment of hypertension, was determined by monitoring in chemical ionization mode with ammonia the [MH]+ ions of the trimethylsilyl derivatives of the drug and of its internal standard ((2H5)betaxolol). Its pharmacokinetic profile obtained following administration of a 20 mg oral dose was characterized by a half-life of 22 h and a bioavailability of 85%. The main acid metabolite formed by elimination of the isopropylamino group may also be determined as the methyl TMS derivative but methylation with BF3-methanol should be used with caution since it may induce the opening of the cyclopropyl group. The routine electron capture determination procedure was compared to this mass spectrometric method and an excellent correlation was found (r = 0.9974). Both procedures have the same sensitivity (1 ng ml-1). Finally it was observed that under electron impact mode betaxolol trimethylsilyl side chain rearranged to lose TMS—O—CH=CH2; this elimination was confirmed by deuterium labelling studies.
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  • 40
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    Biological Mass Spectrometry 11 (1984), S. 47-49 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Platelet activating factor has recently been structurally described as the phospholipid 1-O-alkyl-2-O-acetyl-sn-glycerophosphocholine. It has been reported to be a putative chemical mediator of immunological reactions as well as an antihypertensive agent. A method to quantitate 1-O-alkyl-2-O-acetyl-sn-glycerophosphocholine using deuterium labeled 1-O-alkyl-2-O-acetyl-sn-glycerophosphocholine as an internal standard is described. When 60 ng of the2H3 labeled compound is employed, quantities as low as 10 ng can be measured. The standard curve for this quantitative analysis typically had a correlation coefficient of 0.999 even when the signal saturation effect of FAB was apparent. Thus quantitative analysis using the FAB ionization technique is feasible when one employs the stable isotope internal standard method.
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  • 41
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    Biological Mass Spectrometry 11 (1984) 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 42
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    Biological Mass Spectrometry 11 (1984), S. 142-144 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The development of an analytical method for the determination of brain tryptamine using capillary gas chromatography mass spectrometry (selected ion monitoring) is presented. The method involves solvent extraction of brain homogenates and further derivatization (pentafluoropropionyl derivatives) of the dried extracts. Gas chrmatographic analysis is performed using a bonded phase silica fused capillary column. Selected monitoring of M/z 289 and 292 (isotope dilution technique) allows the determination of tryptamine in adult rat brain (450 ± 73 pg g-1) (X ± SEM), n = 6.
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  • 43
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Acylcarnitines, a biologically important group of metabolites which have thus far eluded characterization by mass spectrometry, exhibit very intense fast atom bombardment mass spectra dominated by parent cations. The combination of high resolution selected ion detection and daughter ion analysis using the linked scan at constant B/E ratio has enabled the unequivocal identification of the acylcarnitines in the urine of children with propionic acidemia, methylmalonic aciduria and Reye's Syndrome. Quantitative analysis of acetylcarnitine and propionylcarnitine in selected samples was accomplished by isotope dilution, utilizing (2H3)acetyl- and (2H5)propionylcarnitines as internal standards. These techniques will allow assessment of the therapeutic use of L-carnitine in these disorders.
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  • 44
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    Biological Mass Spectrometry 11 (1984), S. 450-454 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Five benzothiazole derivatives leached into injections by the rubber plunger-seals of disposable syringes were identified by electron impact (EI) and chemical ionization (CI) mass spectrometry. These are 2-hydroxybenzothiazole, 2-mercaptobenzothiazole, 2-(methylmercaptopto)benzothiazole, 2-(2-hydroxyethoxy)benzothiazole and 2-(2-hydroxyethylmercapto)benzothiazole. 2-Mercaptobenzothiazole is used as a vulcanization accelerator. The other four compounds are formed from the zinc derivative of 2-mercaptobenzothiazole during sterilization with ethylene oxide. Toxicological, technological and legal consequences of the leaching are discussed briefly.
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  • 45
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    Biological Mass Spectrometry 11 (1984), S. 462-465 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A sensitive and efficient analytical procedure was developed to determine phenobarbital-N-glucoside, phenobarbital and p-hydroxyphenobarbital in urine. The stable-isotope labeled internal standards used in this assay were obtained in urine from a subject who ingested 15N-labeled phenobarbital.
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  • 46
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Amiodarone is an antiarrhythmic drug which has received considerable attention in recent years. It has been suggested that the unusual pharmacodynamic characteristics of this drug may be due in part to the influence of active metabolites. Using fast atom bombardment (FAB) mass spectrometry we have identified a new metabolite of amiodarone, the di-N-desethyl analog (DDEA). This metabolite was present in the blood of dogs treated with the parent drug, and showed a greater affinity for myocardium than did the parent drug. The unique features of FAB mass spectrometry over electron impact mass spectrometry was an essential element in facilitating the identification of this new metabolite. Whether or not this metabolite has pharmacologic activity or is responsible for some of the side effects occurring during amiodarone administration is not known.
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  • 47
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    Biological Mass Spectrometry 11 (1984), S. 472-474 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 13C/12C ratios of the carboxyl and methyl carbons of acetic acid were determined by two published methods, using the thermal decomposition of sodium acetate and calcium acetate respectively. Comparison of the results obtained on a variety of samples revealed a systematic disagreement of 4.0% between the two methods. The source of this discrepancy is shown to be a fractionation associated with the calcium acetate method.
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  • 48
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A method has been developed for the determination of flutroline in plasma using capillary gas chromatography and selected ion monitoring detection of the TMS derivative. The method is linear over the concentration range of 3-60 ng ml-1 and was used to define the drug pharmacokinetics and bioavailability in animals and man. A novel method for direct derivatization on the tip of a moving needle injector is described.
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  • 49
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    Biological Mass Spectrometry 11 (1984), S. 475-481 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The desorption ionization mass spectra are reported for two classes of synthetic porphyrins - ‘tailed’ derivatives of deuteroporphyrin IX and meso-substituted derivatized tetraphenylporphines. The mass spectra were obtained by three desorption ionization techniques - fast atom bombardment (FAB), desorption chemical ionization (DCI) and ‘in-beam’ or desorption electron ionization (DEI). The emphasis of this study is to determine the usefulness of the three desorption ionization methods for the molecular weight and side-chain structure determinations of synthetic porphyrins. The molecular parent ions and the major fragmentation pathways are discussed in detail. The DEI method yielded the fewest mass spectra showing molecular parent ions from the compounds studied, whereas FAB gave the most. The major fragmentation pathways were compound dependent and similar for all three ionization methods; generally, those cleavages α and β to carbonyl groups predominated. The FAB spectra showed strong molecular adduct ions in several spectra that could be attributed to an in situ coordination of iron-containing porphyrins with the thio-containing liquid matrix molecules.
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  • 50
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 51
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    Biological Mass Spectrometry 11 (1984), S. 493-493 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 52
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Curiepoint pyrolysis (Py)-mass spectrometry (14 eV electron impact) in various modes of operation and Curiepoint pyrolysis-gas chromatograpy/mass spectrometry (Py-GC/MS) afforded discrimination between homopolyhexoses of different glycosidic linkage type and configuration: (1 → 2)-β-, (1 → 3)-β-, (1 → 4)-α-, (1 → 4)-β-, (1 → 6)-α, (1 → 6)-β-glucan and (1 → 2)-α-mannan. Pyrolysis-mass spectrometry in multichannel averaging mode, combined with discriminant analysis data processing, revealed significant discrimination between all polyhexoses, except for the (1→6) linked polymers. By using preheated telescopic glass tube sample holders, additional specificity of the pyrolysis-mass spectral fingerprint for the (1 → 3) linked carbohydrate was obtained. Pyrolysis-mass spectrometry in time-resolved mode yielded ion profiles, especially characteristic for the (1 → 3)-β-glucan. Py-GC/MS was an additional discriminating dimension (retention time), providing structural information about the pyrolysate constituents, in particular concerning the anhydrohexoses.
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  • 53
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    Biological Mass Spectrometry 11 (1984), S. 494-494 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 54
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    Biological Mass Spectrometry 11 (1984) 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 55
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    Biological Mass Spectrometry 11 (1984), S. 529-534 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The in-beam electron ionization (EI) spectra of quaternary ammonium salts of dextromethorphan and piperidine consist of peaks arising both from thermal degradation products and from the fragmentation of the molecular cation [R4N]+. Mass-analysed ion kinetic energy and ion kinetic energy spectra indicate that several major ions believed to be thermally induced before EI are also produced directly from [R4N]+ fragmentation. However, the contribution of the direct fragmentation of [R4N]+ upon EI is small in comparison to that of the thermal degradation products. This behavior was observed in the conformationally flexible and rigid piperidinium rings studied.
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  • 56
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    Biological Mass Spectrometry 11 (1984), S. 545-548 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Eleven mass spectrometers all connected with a gas chromatograph were used for quantitative determination by the isotopic dilution technique. The purpose of the investigation was to compare the virtual performances of the instruments rather than the routines of the individual laboratories. Therefore, calibration compounds and samples were distributed to the participants. A satisfactory linearity but poor reproducibility was found.
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  • 57
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    Biological Mass Spectrometry 11 (1984), S. 539-544 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of a number of N-acyl-5-aminosalicylic acids and their derivatives is described. These compounds allow the sensitive and specific mass spectrometric determination of unlabelled or deuterium-labelled N-acetyl-5-aminosalicylic acid in biological samples. An in vivo study shows that the labelled compound, administered to rats, is excreted isotopically unchanged to at least 97%, and that no significant deacety lation/acetylation mechanism exists for this metabolite N-acetyl-5-aminosalicylic acid of salicylazosulphapyridine.
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  • 58
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    Biological Mass Spectrometry 11 (1984), S. 583-588 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: In recent years stable isotopes have begun to replace radioisotopes as tracers in metabolic studies. However, these are relatively expensive in the enrichments and quantities required by either conventional gas chromatography/mass spectrometry (GC/MS) or stable isotope ratio analysis (SIRA), the former having good sensitivity but low precision and the latter low sensitivity with more than adequate precision. We describe here a technique for 13C which achieves an appropriate balance between precision and sensitivity for such studies. A combustion interface is placed between the output from a capillary gas chromatograph and a dual collector SIRA mass spectrometer. Compounds eluting from the gas chromatograph are converted into discrete pulses of CO2 gas and intensities of 13CO2 and 12CO2 are measured simultaneously. Typically, 13C relative abundances can be obtained from 0.8 nmol of a C10 compound (8 nmol CO2) with a precision (1SD) of better than 1‰ (0.0011 at.%13C). This permits a reduction by at least a factor of 10 in the quantity of tracer required compared with conventional methods.
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  • 59
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    Biological Mass Spectrometry 11 (1984), S. 594-600 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of metabolites of trinitrotoluene (TNT) have been synthesized and analysed by electron impact (EI) and chemical ionization (CI) mass spectrometry. Identification characteristics of these metabolites by their mass spectra have been determined. Differentiation of isomers is made possible by EI ions which are characteristic of the position of the methyl group with regard to the nitro groups.
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  • 60
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Specific and sensitive procedures have been developed which enabled the structure elucidation of the polypeptide antibiotics (peptaibols), paracelsin isolated from Trichoderma reesei, and of trichotoxin A-50 from Trichoderma viride, by fast atom bombardment and field desorption mass spectrometry. Both peptides were found to exhibit a pronounced microheterogeneity by single and multiple exchange of amino acids. Separation by analytical and semipreparative high-performance liquid chromatography (HPLC) on octadecylsilyl-bonded, reversed-phase columns afforded a series of sequence analogues for each polypeptide. Unequivocal molecular weight and sequence identifications were obtained by positive and negative ion fast atom bombardment (FAB), and field desorption (FD) mass spectrometry, in combination with a single, selective acidolytic cleavage step. Most important for the FAB mass spectral analysis of the extremely hydrophobic polypeptides was the development of oligoethylene-glycols and -glycol ethers as suitable liquid matrix systems, yielding high sensitivity and structurally significant fragment ions of high abundance. At these conditions, the positive ion FAB mass spectra exhibit regular abundant sequence ions with acylium end groups by peptide bond cleavage from the N-terminus, which provided direct sequence determinations for 13 of 20 residues of paracelsin, and for 12 of 18 residues of trichotoxin A-50. The sequence-specific fragmentation precisely continues up to, and ends at the preferential acidolytic cleavage sites (Pro residues). The remaining C-terminal sequence data was obtained by FD and FAB mass spectra of prolyl-hexa- and -heptapeptaibols produced by acidolytic cleavage in situ with aqueous trifluoroacetic acid. In contrast to the original polypeptides, glycerol as a polar matrix was most suitable for the analysis of prolylpeptaibol fragments in the hyrolysis mixture. By contrast, treatment of paracelsins and trichotoxins A-50 with trifluororacetic acid under anhydrous conditions yielded the corresponding trifluoroacetylated polypeptide derivatives which served to ascertain the position of the C-terminal amino alcohol residues. With this procedure, the structures of 14 closely related, partially isobaric sequence analogues of trichotoxin A-50, and of four sequence analogues of paracelsin were determined with amounts of material in the low nanomole range, which provide an exact pattern of the variable and the conservative sequence areas for these polypeptides.
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  • 61
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    Biological Mass Spectrometry 11 (1984), S. 601-601 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
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  • 62
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    Biological Mass Spectrometry 11 (1984), S. 611-615 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Diphenylborinic acid is shown to react with a variety of polyfunctional molecules of biological interest to give products which are easily identifiable by mass spectrometry. The diphenylborinate adducts of amino acids possess extraordinary stability and are separable by reverse phase chromatography. The stability of products is discussed with regard to the nature and stereochemical arrangement of the functional groups involved in complex formation.
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  • 63
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The analysis of antimalarials by high-performance liquid chromatography (HPLC)/mass spectrometry demonstrates a new dimension in specificity along with increased sensitivity compared to conventional HPLC detection methods. Both direct liquid introduction and thermospray HPLC/mass spectrometry interfaces provided molecular weight information as well as characteristic fragment ions for antimalarials not normally amenable to direct probe or gas chromatographic/mass spectrometric techniques. The direct liquid introduction interface, which incorporated a 1/100 split, showed a detection limit of 30 ng using selected ion monitoring. The thermospray technique showed less than 1 ng detection limits using selected ion monitoring.
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  • 64
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The presence of the nucleoside antitumor antibiotic toyocamycin in the fermentation broth was determined by a combination of negative and positive ion fast atom bombardment (FAB) mass spectrometry, high resolution FAB mass spectrometry and mass-analysed ion kinetic energy spectrometry (MIKES). A reasonable limit of detection for toyocamycin in the whole broth was obtained by combining the specificity of mass spectrometry/mass spectrometry (also called tandem mass spectrometry) to FAB. The role played by the fermentation matrix upon the production and the observation of characteristic ions by FAB. using xenon atoms was examined. High-performance liquid chromatography (HPLC) and FAB mass spectrometry were used to monitor toyocamycin at all stages of strain development, fermentation and recovery.
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  • 65
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    Biological Mass Spectrometry 11 (1984), S. 629-632 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: An analytical method to determine the concentration of bupropion in human plasma has been developed using a deuterium-labeled analog as internal standard and selected ion monitoring applied to an extract of plasma samples taken as part of a clinical trial of this antidepressant. In all, 15 depressed outpatients were randomly assigned to bupropion in a double-blind study which included weekly evaluation of their clinical condition. A good correlation was found between the results obtained by this assay and by a radioimmunoassay technique currently in use. While no simple correlation between plasma concentration and therapeutic improvement was noted, the majority of subjects showed mild to marked amelioration of symptoms and those having mean concentrations above 35 ng ml-1 had significant improvement in their test scores. Interpretation of the mass spectra of both the labeled and unlabeled drug revealed an apparent violation of the ‘even-electron rule’.
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  • 66
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    Biological Mass Spectrometry 11 (1984), S. 633-642 
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This report describes the use of direct chemical ionization mass spectrometry with ammonia as the reagent gas (NH3-DCI) for structure analysis of underivatized, permethylated and permethylated and reduced glycosphingolipids. In contrast to ionization by electron impact the NH3-DCI mass spectra exhibit intense molecular and carbohydrate sequence-related ions using microgram amounts of sample. Underivatized glycosphingolipids with up to two sugar residues yield abundant protonated and ammonia-cationized molecular ions and structurally significant fragments. Permethylation in conjunction with NH3-DCI can be used to obtain molecular weight as well as oligosaccharide sequence and branching information on neutral, acidic and complex-type glycosphingolipids with up to five sugar residues. Reduction of the permethylated derivatives gives rise to several new, structurally significant fragments in the corresponding NH3-DCI mass spectra which enable fatty acid and base compositions to be determined. Isotopically labeled reagent gases have been used to confirm the assignment of fragment structures and to demonstrate that the ions observed are unique to the NH3-DCI mass spectra.
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  • 67
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    International Journal for Numerical Methods in Fluids 4 (1984), S. 13-24 
    ISSN: 0271-2091
    Keywords: Gas Networks ; Computational Methods ; Simulation Optimization ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A technique is presented for calculating the transient flow in high pressure transportation systems where both simple systems (without compressors) and systems with compressors have been taken into consideration. A partial differential equation characterizing the dynamic gas flow through a pipeline and a numerical scheme for its solution are considered. A method of computing node pressures is also characterized.
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  • 68
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    International Journal for Numerical Methods in Fluids 4 (1984), S. 106-108 
    ISSN: 0271-2091
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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  • 69
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    International Journal for Numerical Methods in Fluids 4 (1984) 
    ISSN: 0271-2091
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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  • 70
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    International Journal for Numerical Methods in Fluids 4 (1984), S. 127-145 
    ISSN: 0271-2091
    Keywords: Finite Element ; Bénard Connection ; Bifurcation ; Continuation ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The problem of fluid motion in a cavity with rigid sidewalls that is heated uniformly from below is studied by the finite-element method. The techniques of parameter-stepping and monitoring the determinant of the Jacobian matrix to find bifurcations are used. Results are presented for width-to-height ratios in the range 1 to 4, and for three different boundary conditions on the horizontal surfaces, namely both rigid, both free, and rigid bottom with free top. The non-linear branches above the critical Rayleigh number are examined. Extensions to non-Boussinesq flow are trivial.
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  • 71
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    International Journal for Numerical Methods in Fluids 4 (1984), S. 203-205 
    ISSN: 0271-2091
    Keywords: Incompressible Fluid Flows ; Cavity ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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  • 72
    ISSN: 0271-2091
    Keywords: Potential Flows ; Navier-Stokes Problems ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: An approach for the numerical solution of flow problems based on the concept of fundamental solutions of differential equations is described. This approach uses the finite element methodology but does not rely on the concept of variational principle or that of residuals. The approach is shown to be well-suited for many types of flow problems. Various applications of this approach are discussed in this paper, with particular emphasis placed on the solution of potential flows and viscous flows containing appreciable regions of separation.
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  • 73
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    International Journal for Numerical Methods in Fluids 4 (1984), S. 247-269 
    ISSN: 0271-2091
    Keywords: Finite Elements ; Navier-Stokes ; Driven Cavity ; Flow Past a Cylinder ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: We present a simple and efficient finite element method to solve the Navier-Stokes equations in primitive variables V, p. It uses (a) an explicit advection step, by upwind differencing. Improvement with regard to the classical upwind differencing scheme of the first order is realized by accurate calculation of the characteristic curve across several elements, and higher order interpolation; (b) an implicit diffusion step, avoiding any theoretical limitation on the time increment, and (c) determination of the pressure field by solving the Poisson equation. Two laminar flow calculations are presented and compared to available numerical and experimental results.
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  • 74
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    International Journal for Numerical Methods in Fluids 4 (1984), S. 271-281 
    ISSN: 0271-2091
    Keywords: Collocation ; Moving Mesh ; Advection-Diffusion ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A collocation method based on multiple regions with moving boundaries placed in a flow field in which convection effects dominate, is proposed. By making the moving boundaries of the regions coincide with moving sharp fronts present in the solution of convection dominated problems, and thereby allowing higher concentration of meshes to be placed about the fronts, the proposed method is able to achieve very high accuracy. By having a moving mesh, the Peclet number characterizing the flow field depends upon velocity relative to a moving mesh in a region. Consequently by choosing proper velocities of the moving boundaries, the value of this Peclet number can be made as small as desired. The traditional collocation method based on centred discretization, when applied to each region in the field, produces oscillation free solutions even when the values of Peclet number based on absolute velocity are extremely large. In view of these characteristics the method appears to be an excellent candidate for the solution of any two-phase flow problem containing sharp fronts.
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  • 75
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    International Journal for Numerical Methods in Fluids 4 (1984) 
    ISSN: 0271-2091
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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  • 76
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    International Journal for Numerical Methods in Fluids 4 (1984), S. 283-290 
    ISSN: 0271-2091
    Keywords: Prandtl's Equation ; Singular Integrodifferential Equations ; Quadrature Method ; Natural Interpolation Formula ; Principal Value Integrals ; Gauss- and Lobatto-Chebyshev Quadrature Rules ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Prandtl's singular integrodifferential equation and related equations appear in problems of aerofoil and propeller theory in fluid mechanics. Here a natural interpolation formula for the approximation to the unknwon function of Prandtl's equation when this is solved numerically by the direct quadrature method, based on the Gauss- and Lobatto-Chebyshev quadrature rules, is proposed. This interpolation formula is analogous to Nyström's natural interpolation formula for Fredholm integral equations of the second kind and the corresponding formula for singular integral equations. Numerical applications of the same formula are also made.
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  • 77
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    International Journal for Numerical Methods in Fluids 4 (1984), S. 291-302 
    ISSN: 0271-2091
    Keywords: Finite Elements ; MHD Flows ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A finite element method is given to obtain the numerical solution of the coupled equations in velocity and magnetic field for unsteady MHD flow through a pipe having arbitrarily conducting walls. Pipes of rectangular, circular and triangular sections have been taken for illustration. Computations have been carried out for different Hartmann numbers and wall conductivity at various time levels. It is found that if the wall conductivity increases, the flux through a section decreases. The same is the effect of increasing the Hartmann number. It is also observed that the steady state is approached at a faster rate for larger Hartmann numbers or larger wall conductivity. Selected graphs are given showing the behaviour of velocity, induced magnetic field and flux across a section.
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  • 78
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    International Journal for Numerical Methods in Fluids 4 (1984), S. 497-497 
    ISSN: 0271-2091
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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  • 79
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    International Journal for Numerical Methods in Fluids 4 (1984) 
    ISSN: 0271-2091
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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  • 80
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    International Journal for Numerical Methods in Fluids 4 (1984), S. 477-496 
    ISSN: 0271-2091
    Keywords: Gas Dynamics ; Finite Difference Schemes ; Shock Localization ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: We consider a problem on shock wave localization in the numerical solution of one-dimensional unsteady problems of gas dynamics in Eulerian variables obtained on the basis of finite difference shock-capturing schemes. An optimization method for strong discontinuity localization proposed previously by Miranker and Pironneau is investigated by means of methods of classical variational calculus. This method may be difficult to implement when the entropy condition is included in the formulation of Miranker and Pironneau's optimization problem as an active constraint. In this connection we suggest an alternative optimization problem using artificial viscosity in the variational principle. It is shown theoretically that the application of such a variational principle yields a trajectory which coincides with the true discontinuity trajectory in the case of a shock wave moving at a constant speed. On the basis of this modification one more algorithm is proposed which reduces the shock localization problem to a problem of minimization of a univariate function. Numerical tests corroborate completely the theoretical conclusions. In particular, a higher shock localization accuracy is obtained on the basis of the proposed algorithms as compared to the original Miranker-Pironneau method.
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  • 81
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    International Journal for Numerical Methods in Fluids 4 (1984), S. i 
    ISSN: 0271-2091
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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  • 82
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    International Journal for Numerical Methods in Fluids 4 (1984), S. i 
    ISSN: 0271-2091
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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  • 83
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    International Journal for Numerical Methods in Fluids 4 (1984), S. 499-509 
    ISSN: 0271-2091
    Keywords: Critical Flow Rate ; Finite Elements ; Free Surface ; Weir ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Computing critical flows in hydraulics involves three problems in one: the internal flow problem, the location of the free surface and the determination of the critical flow rate. The subject can involve such difficulties as non-uniqueness, non-existence, ill-conditioning and catastrophes.This paper discusses the difficulties relating to computing critical flows over weirs. A new rapidly convergent method of determining the critical flow rate is presented and various results are shown using it with finite element discretization and with a new streamline shifting method. Numerical results are in good agreement with published data, both numerical and experimental.
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  • 84
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    International Journal for Numerical Methods in Fluids 4 (1984), S. 511-517 
    ISSN: 0271-2091
    Keywords: Approximation ; Cubic Splines ; Orthogonal Collocation ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A well-known Stokes problem is discussed by a cubic spline collocation method. Two consecutive cubic splines are obtained for the problem. The results by this method are compared with those of an orthogonal collocation method. The selection of the length of the subintervals of the range of the boundary value problem is also justified. The results obtained by these two methods are compared with the analytic solution. The methods involve simple algebra, and hence the calculations do not require the help of a computer. Necessary error analysis has been carried out.
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  • 85
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    International Journal for Numerical Methods in Fluids 4 (1984), S. 519-537 
    ISSN: 0271-2091
    Keywords: Boundary-Fitted Co-ordinates ; Incompressible Flow ; 2D and 3D ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: For three-dimensional fluid flows in complex geometries, it is convenient to make predictions using a non-orthogonal boundary-fitted mesh. The present paper describes an economical method of solving the equations of motion for two and three dimensional problems using such meshes. The locations on the mesh at which the depenent variables are calculated, and the methods used to solve the equations, are key issues in the development of a successful algorithm; these are discussed in the present paper. Results obtained when the proposed method is applied to several problems are also described. The method is intended for flows in which compressibility effects do not dominate.
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  • 86
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    International Journal for Numerical Methods in Fluids 4 (1984) 
    ISSN: 0271-2091
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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  • 87
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    International Journal for Numerical Methods in Fluids 4 (1984), S. 710-710 
    ISSN: 0271-2091
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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  • 88
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    International Journal for Numerical Methods in Fluids 4 (1984), S. 711-724 
    ISSN: 0271-2091
    Keywords: Finite-Volume Method ; Numerical Diffusion ; Upstream Weighted Differencing ; Skew Upstream Differencing ; Turbulent Recirculating Flow ; Turbulence Model ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Predictions are reported for two-dimensional, steady, incompressible flows over rearward-facing steps for both laminar and turbulent conditions. The standard k-∊ turbulence model was used for the turbulent flow. Attention was focused on obtaining accurate solutions to the differential equations. It is concluded that some of the serious discrepancies that have occurred between prediction and observation, and attributed in earlier studies to the inadequacy of the turbulence model, may have been due to the inaccuracy of the solution.
    Additional Material: 11 Ill.
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  • 89
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    International Journal for Numerical Methods in Fluids 4 (1984), S. 749-764 
    ISSN: 0271-2091
    Keywords: Hyperbolic Conservation Equation ; Finite Elements ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Several explicit schemes are presented for triangular P0 and P1 finite elements. A first-order accurate upwind P0 scheme is compared to a FLIC type method. A second-order accurate Richtmyer scheme is constructed. Applications are given for the Euler system of conservation laws in the 2-dimensional case.
    Additional Material: 14 Ill.
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  • 90
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    International Journal for Numerical Methods in Fluids 4 (1984), S. 725-747 
    ISSN: 0271-2091
    Keywords: Ray Methods ; Water Waves ; Refraction ; Diffraction ; Coasts ; Harbours ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Ray methods are used in coastal and harbour wave disturbance investigations where the area to be modelled is large compared to the wavelength. The interpretation of forward-plotted ray diagrams, once obtained, has always been a difficult problem. The technique described in this paper calculates wave amplitudes during the ray plotting process and requires only minor modifications to existing ray plotting programs. The idea is to superimpose a grid of square elements over the entire sea area under study, and to perform a spatial averaging of the rays crossing each square element. This ‘square-averaging’ technique has a number of advantages. It smooths the rapid amplitude variations near caustics, calculates the interference of several wave trains, and generates amplitudes automatically in a square array covering the whole studied sea area. Two types of sensitivity tests are carried out. These tests are designed to determine the accuracy of the predicted wave amplitudes with respect to: (1) the square size per wavelength, and (2) the ray density. These two factors largely determine the computing storage, time and cost of a ray model. An upper limit on the square size per wavelength and a lower limit on the ray density are obtained.
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  • 91
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    International Journal for Numerical Methods in Fluids 4 (1984), S. 801-801 
    ISSN: 0271-2091
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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  • 92
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    International Journal for Numerical Methods in Fluids 4 (1984), S. 802-802 
    ISSN: 0271-2091
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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  • 93
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    International Journal for Numerical Methods in Fluids 4 (1984), S. 1013-1025 
    ISSN: 0271-2091
    Keywords: Stream Function ; Viscous Flow ; Non-conforming Elements ; Interface Penalties ; Reduced Integration ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A finite element method for solution of the stream function formulation of Stokes flow is developed. The method involves complete cubic non-conforming (C0) triangular Hermite elements. This element fails the patch test. To correct the element and produce a convergent method we employ a penalty method to weakly enforce the desired continuity constraint on the normal derivative across the inter-element boundaries. Successful use of the method is demonstrated to require reduced integration of the inter-element penalty with a 1-point Gauss rule. Error estimates relate the optimal choice of penalty parameter to mesh size and are corroborated by numerical convergence studies. The need for reduced integration is interpreted using rank relations for an associated hybrid method.
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  • 94
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    International Journal for Numerical Methods in Fluids 4 (1984), S. 1097-1098 
    ISSN: 0271-2091
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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  • 95
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    International Journal for Numerical Methods in Fluids 4 (1984), S. 1083-1095 
    ISSN: 0271-2091
    Keywords: Turbomachines ; Finite Volume ; Consistency ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The aim of this contribution is to investigate the consistency and order of accuracy of different control surfaces used for finite area blade-to-blade flow calculations. The following cases will be treated: a hexagonal element, a trapezoidal element, a bitrapezoidal element and a quadrilateral element. Finally, the consistency conditions will be discussed and compared with respect to a cascade flow application.
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  • 96
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    International Journal for Numerical Methods in Fluids 4 (1984), S. 1099-1099 
    ISSN: 0271-2091
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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  • 97
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    International Journal for Numerical Methods in Fluids 4 (1984) 
    ISSN: 0271-2091
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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  • 98
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    International Journal for Numerical Methods in Fluids 4 (1984), S. 1117-1136 
    ISSN: 0271-2091
    Keywords: Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: We describe in this paper some new methods for solving the shallow water flow problem; this problem is composed of two coupled non-linear equations. First a fractional step method is used to decouple the difficulties due to the convection and the propagation. The diffusion propagation step amounts to solving two coupled linear equations on the water depth and the fluxes. We used then some quasi-direct decomposition techniques to decouple the unknowns, leading to symmetric systems only. In addition some non-trivial boundary conditions on the flux are examined. Particularly we are interested to get decoupled systems on the two components of the flux. Numerical tests are presented to enlighten the behaviour and the capabilities of the method. Finally an industrial example is treated on the Dunkirk harbour.
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  • 99
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    International Journal for Numerical Methods in Fluids 4 (1984), S. 1101-1115 
    ISSN: 0271-2091
    Keywords: Numerical Solution ; Navier-Stokes Equations ; 2-D Steady, Laminar Flows ; ADI Method ; Spline Interpolating Polynomials ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: The present paper provides an improved alternating direction implicit (ADI) technique as well as high-order-accurate spline ADI method for the numerical solution of steady two-dimensional incompressible viscous flow problems. The vorticity-stream function Navier-Stokes equations are considered in a general curvilinear coordinate system, which maps an arbitrary two-dimensional flow domain in the physical plane into a rectangle in the computational plane. The stream function equation is parabolized in time by means of a relaxation-like time derivative and the steady state solution is obtained by a time-marching ADI method requiring to solve only 2 × 2 block-tridiagonal linear systems. The difference equations are written in incremental form; upwind differences are used for the incremental variables, for stability, whereas central differences approximate the non-incremental terms, for accuracy, so that, at convergence, the solution is free of numerical viscosity and second-order accurate. The high-order-accurate spline ADI technique proceeds in the same manner; in addition, at the end of each two-sweep ADI cycle, the solution is corrected by means of a fifth-order spline interpolating polynomial along each row and column of the computational grid, explicitly. The validity and the efficiency of the present methods are demonstrated by means of three test problems.
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  • 100
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    Electronic Resource
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 4 (1984), S. 1137-1148 
    ISSN: 0271-2091
    Keywords: Free Surface Flows ; Computation ; Kantorovich Method ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Computing free surface gravity flows involves basically two coupled problems, namely, the location of the free surface position and the determination of the internal flow field (for assumed values H0 and Q of the total head and discharge, respectively).Solution techniques are invariably based on iterative procedures, but those that iterate between the two coupled problems may become unstable.In this paper we present a computational method in which the coupling is kept throughout the process of iteration. This is achieved by converting the coupled problems (by means of the Kantorovich method) into the single problem of finding a set of streamlines, including that of the free surface. These streamlines are moved (iteratively) to satisfy the stationary conditions of the governing variational principle.The algorithm is very stable and converges rapidly. It is also easy to implement to solve various types of steady flows with a free surface under gravity.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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