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We study a radial basis function collocation method (RBFCM) to discretize a coupled nonlinear Schrdinger equation (CNLSE) that governs a two dimensional rotating Bose-Einstein condensate (BEC) with an angular momentum rotation term. We exploit a RBFCM-continuation method (RBFCM-CM) to trace the solution curve of the CNLSE. We compare the performance of the RBFCM-CM with the FEM-CM. We observe that the RBFCM-CM is very robust in a coarse grid for resolving the ground state solution with many vortices when the angular momentum rotation is close to the limit. Numerical results demonstrate the efficiency and accuracy of the RBFCM-CM for computing the superfluid density of the ground level of the BEC.

LiAlxOy films with thicknesses of 65–200 nm were deposited by the ALD technique on an Mg–10Li–0.5Zn alloy. The ALD-deposited LiAlxOy films have an amorphous structure and exhibit properties of low friction coefficient, high hardness/elastic (H/E) ratio, strong adhesion, smooth surface roughness and conformable coverage. These excellent properties of ALD-deposited LiAlxOy films can significantly improve the wear performance and cavitation–erosion resistance of Mg–10Li–0.5Zn alloy.

Ultraviolet (UV) light-emitting diodes composed of n-ZnO:Al-SiO2-ZnO nanocomposite/p-GaN:Mg heterojunction were fabricated on the (0002) Al2O3 substrate. A SiO2 layer embedded with ZnO nanodots was prepared on the p-type GaN using spin-on coating of SiO2 nanoparticles together with atomic layer deposition (ALD). An n-type Al-doped ZnO layer was deposited also by ALD. The SiO2-ZnO nanocomposite layer accomplishes a role of the current blocking layer and also causes, by its low refractive index, the increase in the light extraction efficiency from n-ZnO. Significant UV electroluminescence from n-ZnO was achieved at a low forward-bias current of 1.8 mA. Strong UV emission arising from impact ionization in GaN, ZnO, and GaN:Mg states was also observed at reverse breakdown bias.

Sedimentation is a convenient and inexpensive method of separating solids from liquids. Electrokinetic effects play a large role in such separations. The sedimentation of fine particles suspended in nonaqueous media, such as toluene, containing various quantities of asphaltenes was studied. Settling rates and solid concentrations in a sedimentation column were measured by an X-ray densitometer. Sedimentation was rapid at low concentrations of asphaltenes due to flocculation. At asphaltene concentrations of greater than about 0.1 %, adsorption of asphaltenes on the particles caused a marked retardation of settling. On the application of an electric field settling rates increased. In Part II of this paper, a one-dimensional hydrodynamic model for the sedimentation of fine particles was developed. The basic model and its modified form, a diffusion-type equation, were both solved by the method of characteristics. The predicted settling rates and the solids concentrations in the settling column agreed with our experimental observations. The effect of the electrical field on settling rates was also included in the hydrodynamic sedimentation model.

A one-dimensional hydrodynamic model for the sedimentation of multisized particles was developed. The basic model was solved by the ICE numerical method, using a modified K-FIX computer code. The predicted settling rates agree with Selim's et al. settling data of two heavy species and Fessas and Weiland's experiments of heavy, buoyant two-species settling. The model also computes reasonable concentration profiles in the settler. To effectively simulate the sedimentation of multisized fine colloidal particles in non-aqueous media, the model was modified to be a diffusion-type matrix equation and solved by the method of characteristics. Surface charge effect of colloidal particles was included in the model The predicted concentration profiles for the settling of fine illite particles in toluene with asphaltene agree well with the recent experimental data reported by Shih et al.

A new, very stable dithiocarbamate, bis( n -butyl-2-naphthylmethyldithiocarbamate) zinc(II), has been synthesized and its use in trace metal determination by high-performance liquid chromatography (h.p.l.c.) has been investigated. Metal complexes of this ligand are thermodynamically stable and kinetically inert at the 1 × 10 -8 M level. Various metal complexes including nickel(II), iron(III), copper(II), mercury(II), and cobalt(II) have been “baseline” separated by nonpolar stationary-phase h.p.l.c. The detection limits are about 1–2 ng with a variable-wavelength absorbance detector.

The determination of traces of metals by high-performance liquid chromatography of their n-butyl-2-naphthylmethyldithiocarbamate (BNMDTC) complexes on a nonpolar stationary phase, with a post-column photochemical detector is described. Metal complexes of this ligand are thermodynamically stable and kinetically inert towards dissociation. To provide low detection limits, a photochemical reactor was developed to generate a fluorescent product. A major product of the photolysis of BNMDTC complexes is identified as the highly fluorescent n-butyl-2-naphthyl-methylamine. Detection of metal ions as BNMDTC complexes at the 10−8 M level is feasible. Iron, nickel, mercury and cobalt complexes are readily determined.

Dry, electrostatic separation is a potentially efficient method of removing pyrites from coal. However, progress in the past was hampered by a lack of a quantitative analysis of the process. To help design better separation equipment, the authors developed a hydrodynamic model of separation of pyrites from coal in a batch electrofluidized bed. The simulations were done on a Cray-2 computer. The input variables include the surface charge of the particles and the solids stress, which were measured. Realistic shapes and sizes of bubbles were computed with and without an applied electric field for a two-dimensional bed with a central jet. The bubble sizes and the rising velocities were smaller with an applied field, consistent with observations. Computed electrophoretic mobilities in the fluidized bed will be useful for a better design of continuous beds.

The determination of traces of metals by high-performance liquid chromatography of their n-butyl-2-naphthylmethyldithiocarbamate complexes, with a fixed-wavelength absorbance detector, is described. Metal complexes of this ligand are thermodynamically stable and kinetically inert towards dissociation. Various metal complexes, including those of nickel(II), iron(III), mercury(II), thallium(III), platinum(II), palladium(II), copper(II), and cobalt(II) are readily determined. The practical aspects of their separation on various nonpolar stationary phase columns are discussed. The detection limits compare very favorably with those of atomic spectrometry and are about 0.1 ng or approximately 10nM.

A simple method has been developed to minimize the interferences related to the metal parts of an analytical system used for trace metal analysis by HPLC. This is accomplished by blocking the exposed metal surfaces with an organosilane. The effect of the silanized stainless steel frits has been demonstrated by injecting diethyldithiocarbamate into columns with and without high metal surface area components. The coating of the silane is quite stable for routine use.