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  • 1
    Electronic Resource
    Electronic Resource
    An automated apparatus for measuring the tensile strength and compressibility of fine cohesive powders (2000)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 71 (2000), S. 2791-2795 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: This paper describes an apparatus based on a novel use of a powder bed, whereby the relationship between consolidation stress, tensile strength, and free volume of fine powder is measured. The powder to be tested is first initialized to a reproducible state. The initialized powder is next consolidated either beyond its own weight or below its own weight by means of a controlled flow of gas. An ultrasonic device measures the height of the bed, thus providing an average value of the powder free volume. Next the consolidated bed of powder is subjected to a slowly increasing gas flow, so directed as to put the powder under tension. The overpressure causing the powder to break provides a measure of the tensile strength of the powder, which in turn is a function of the consolidation and free volume. The relationship between consolidation stress, tensile strength, and free volume is related to powder flowability. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1150694
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  • 2
    Electronic Resource
    Electronic Resource
    Destabilization of plane Poiseuille flow of insulating liquids by unipolar charge injection (1997)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 9 (1997), S. 399-406 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The electrohydrodynamic instabilities of plane Poiseuille flow when subjected to an orthogonal arbitrary unipolar injection of charge has been studied. Appropriate boundary conditions for the perturbed charge density in the space charge limited current regime in the presence of forced flows has been derived. The effect of the injection level on the stability of the flow is analyzed, as well as the role played by the ratio of the hydrodynamic to the true ionic mobility. It is shown that in the low Reynolds number region traverse rolls are destabilized more strongly as the ratio of mobilities decreases. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.869477
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  • 3
    Electronic Resource
    Electronic Resource
    One-dimensional models for slender axisymmetric viscous liquid bridges (1996)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 8 (1996), S. 2837-2846 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A set of one-dimensional models, previously derived for liquid jets, is generalized to viscous liquid bridges by applying suitably modified boundary conditions at the anchoring disks. A linear analysis for small-amplitude perturbations around the cylindrical static solution is performed. The oscillation frequencies and growth factors so obtained are compared to the already known linear three-dimensional results for a wide range in both the slenderness and viscosity. The relative error of each model is studied in terms of the typical axial length. Good agreement is found for slender enough bridges. The existence of boundary layers for weakly dissipative liquid bridges in the context of one-dimensional models is also discussed. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.869087
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  • 4
    Electronic Resource
    Electronic Resource
    Bifurcation diagrams of axisymmetric liquid bridges subjected to axial electric fields (1994)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 6 (1994), S. 3580-3590 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The stability of dielectric liquid bridges between plane parallel electrodes when an electric potential difference is applied between them is studied for an axisymmetric configuration regarding arbitrary volume, axial gravity, and unequal coaxial anchoring disks attached to the electrodes. The stability is determined from the bifurcation diagrams related to the static problem. Two mathematical approaches are presented which are different in scope. First, the Lyapunov–Schmidt projection technique is applied to give the liquid bridge bifurcation diagrams for the bridge considered as an imperfect cylindrical one. The imperfection parameters, i.e., the relative difference of radii to the mean diameter, the deviation from the cylindrical volume, and the gravitational Bond number, are assumed to be small. Second, a Galerkin/finite element technique is used to obtain numerically bifurcation diagrams for arbitrary values of all the parameters. Agreement between both methods is good for small enough values of the imperfection parameters. The effect of the polarization charges existing at the free surface is highlighted. As in the absence of applied electric field, the gravitational Bond number and the relative difference of radii separately decrease the stability of the liquid column, but both effects conveniently combined may cancel out.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.868416
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  • 5
    Electronic Resource
    Electronic Resource
    One-dimensional models for slender axisymmetric viscous liquid jets (1994)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 6 (1994), S. 2676-2689 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A one-dimensional analysis of slender axisymmetric viscous liquid jets is considered. A set of one-dimensional models is derived by substituting a truncated Taylor series in the radial coordinate into the Navier–Stokes equations and boundary conditions at the interface. The relative error, defined as the order of magnitude of the neglected terms divided by the order of the retained ones, is small if the dimensionless wave number k is small enough. The Lee slice model is generalized to take into account viscosity, the relative error being k2. A new model having a parabolic radial dependence for the axial velocity is developed, with a relative error k4. The Cosserat model comes from the introduction of the mean axial velocity into the previous one, but an inconsistency arises from neglecting some viscous terms of the same order as those retained. A new model for the mean axial velocity is derived. It conserves the same inertial contribution but avoids the above-mentioned problem by estimating the involved terms instead of neglecting them. Therefore the relative error is k4 for any value of viscosity. Linear stability analysis is performed for the infinite jet. Results are compared with the exact linear solution given by Lord Rayleigh. The main features predicted in the derivation of the one-dimensional models manifest themselves in the linear case.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.868157
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  • 6
    Electronic Resource
    Electronic Resource
    Experiments on dielectric liquid bridges subjected to axial electric fields (1994)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 6 (1994), S. 3206-3208 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Experimental determination of the critical axial electric field needed to hold a nonconducting liquid bridge of given slenderness is presented. The Plateau tank technique is used to minimize gravity forces on earth. Improvement of previous data is achieved by determining the gravitational Bond number. The results are compared to numerical calculations of the stability limits, showing a good agreement.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.868103
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  • 7
    Electronic Resource
    Electronic Resource
    Effect of viscosity on the stability of an interface subjected to high-frequency magnetic fields (1996)
    [S.l.] : American Institute of Physics (AIP)
    Physics of Fluids 8 (1996), S. 1907-1916 
    Details
    ISSN: 1089-7666
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Natural frequencies and stability criterion for an interface between a liquid metal and an insulating gas subjected to a parallel alternating magnetic field are obtained, with particular attention to the influence of the small viscosity of the liquid metal. The governing equations are derived under the assumption of small magnetic Reynolds number and the neglect of thermal effects. Results indicate that when the liquid metal is above the insulating gas the viscous-magnetic terms may play the role of a negative viscosity, leading to overstability close to the nonviscous critical solution of Rayleigh–Taylor type. Thus, the criterion of stability changes. Apart from this region of overstability the natural frequencies of the nonviscous and viscous solutions are very similar, the changes being of the order of the nondimensional viscosity. Similarly, the velocity perpendicular to the interface does not deviate appreciably from the nonviscous solution. On the contrary, the tangential velocity differs markedly from the nonviscous solution. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.869104
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  • 8
    Electronic Resource
    Electronic Resource
    The EuTrans Spoken Language Translation System (2000)
    Springer
    Machine translation 15 (2000), S. 75-103 
    Details
    ISSN: 1573-0573
    Keywords: finite-state models ; grammatical inference ; speech translation ; subsequential transducers ; transducer learning
    Source: Springer Online Journal Archives 1860-2000
    Topics: Linguistics and Literary Studies , Computer Science
    Notes: Abstract The EuTransAll project aims at using example-based approaches for the automatic development of Machine Translation systems accepting text and speech input for limited-domain applications. During the first phase of the project, a speech-translation system that is based on the use of automatically learned subsequential transducers has been built. This paper contains a detailed and mostly self-contained overview of the transducer-learning algorithms and system architecture, along with a new approach for using categories representing words or short phrases in both input and output languages. Experimental results using this approach are reported for a task involving the recognition and translation of sentences in the hotel-receptioncommunication domain, with a vocabulary of 683 words in Spanish. Atranslation word-error rate of 1.97% is achieved in real-timefactor 2.7 on a Personal Computer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1011116115948
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  • 9
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    Self-Diffusion in a Gas-Fluidized Bed of Fine Powder (2001)
    American Physical Society
    Details
    Publication Date: 2001-04-02
    Print ISSN: 0031-9007
    Electronic ISSN: 1079-7114
    Topics: Physics
    Published by American Physical Society
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  • 10
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    Flow Regimes in Fine Cohesive Powders (1999)
    American Physical Society
    Details
    Publication Date: 1999-02-08
    Print ISSN: 0031-9007
    Electronic ISSN: 1079-7114
    Topics: Physics
    Published by American Physical Society
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