A characteristic nonoverlapping domain decomposition method for multidimensional convection‐diffusion equations

We develop a quasi‐two‐level, coarse‐mesh‐free characteristic nonoverlapping domain decomposition method for unsteady‐state convection‐diffusion partial differential equations in multidimensional spaces. The development of the domain decomposition method is carried out by utilizing an additive Schwarz domain decomposition preconditioner, by using an Eulerian‐Lagrangian method for convection‐diffusion equations and by delicately choosing appropriate interface conditions that fully respect and utilize the hyperbolic nature of the governing equations. Numerical experiments are presented to illustrate the method. © 2004 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2005     

Incompressible quantum liquids and new conservation laws

In this Letter, we investigate a class of Hamiltonians which, in addition to the usual center-of-mass momentum conservation, also have center-of-mass position conservation. We find that, regardless of the particle statistics, the energy spectrum is at least q-fold degenerate when the filling factor is p/q, where and are coprime integers. Interestingly, the simplest Hamiltonian respecting this type of symmetry encapsulates two prominent examples of novel states of matter, namely, the fractional quantum Hall liquid and the quantum dimer liquid. We discuss the relevance of this class of Hamiltonian to the search for featureless Mott insulators.     

Drag amplification of long flexible riser models undergoing multi-mode VIV in uniform currents

Measurement data of long flexible riser models are used to study the drag amplification due to multi-mode vortex induced vibration (VIV). The riser model was towed in a towing tank, and vibration along its length was measured indirectly at a set of discrete points using accelerometers, along with the total drag and lift forces on the model. These data were used to fit expressions for the drag amplification taking into account the spatial variation of the vibration amplitude along the riser length. The results were compared with the existing empirical expression used in the VIV analysis tool SHEAR7 as well as other test data. It was found that the expression in SHEAR7 agrees well with the test data. However, for larger vibration amplitudes, it appears to under-predict the drag amplification.     

Photochemistry of the anthracene chromophore: Triplet-sensitized isomerizations of dianthrylethanes

The photochemical isomerization of 1,2-di(9-anthryl)ethane can be sensitized by biacetyl to proceed by intramolecular Diels-Alder reaction. The molecular geometry of dianthrylethanes affects their triplet state reactivity.     

Separation of the isochromatics-isopachics patterns by use of retarders in holographic photoelasticity

By double passing the object beam in photoelastic-holographic interferometry, separation of the isochromatic-isopachic patterns can be achieved. The object beam must then interact with a suitable polarizing element between the first and second pass. This problem is analyzed using Jones' matrices. This analysis shows that, apart from active and passive rotators, half-wave and quarter-wave retarders can also be used as polarizing elements. Possible experimental arrangements of the method are reviewed and experimental verifications are presented.     

API stepsize control for the numerical solution of ordinary differential equations

A control-theoretic approach is used to design a new automatic stepsize control algorithm for the numerical integration of ODE's. The new control algorithm is more robust at little extra expense. Its improved performance is particularly evident when the stepsize is limited by numerical stability. Comparative numerical tests are presented.     

A reinvestigation of the thermal rearrangements of naphthvalene

The previously reported thermal transformation of naphthvalene to benzofulvene has been shown to be a catalyzed process; naphthvalene rearranges to naphthalene under flow pyrolysis conditions.     

Studies of hydrogen bonding: Part XXIX. An experimental and theoretical approach to the structure of nitriles and of hydrogen-bonded complexes with phenol

Dipole moments, μ_a, of four nitriles, have been determined experimentally and calculated by the CNDO/2 method. The results obtained can be accounted for in terms of a planar trimer parallel-antiparallel model held together in clusters. Experimental and CNDO/2 calculated dipole moments of hydrogen-bonded complexes between nitriles and phenol indicate strongly that the O-H proton in phenol is located perpendicular to the triple bond.     

The surface tension of concentrated aqueous solutions of 1.1-electrolytes measured by means of Wilhelmy and laser light scattering methods

Surface tension measurements were made on concentrated (<4 moles/kg) aqueous solutions of the following 1.1-electrolytes: KF, KCl, KI, HCl, and HNO₃. Two different measurement techniques were used: the Wilhelmy slide method and a method based on the scattering of laser light by small amplitude liquid surface waves. The surface tension determined by the two methods agrees within ±0.5% and for each solution it is found to vary almost linearly with concentration. The shear viscosity was also measured for these solutions by means of the laser method and a standard flow viscosimeter. The measured values were found to agree within ±5%.