We investigate the errors associated with the use of circular cylinders as surrogates for hexagonal columns in computing the optical properties of pristine ice crystals at infrared (8-12-microm) wavelengths. The equivalent circular cylinders are specified in terms of volume (V), projected area (A), and volume-to-area ratio that are equal to those of the hexagonal columns. We use the T-matrix me...

A double column procedure was devised for simultaneous estimation of norepinephrine, normetanephrine, dopamine, 3-methoxytyramine, and 5-hydroxytryptamine in brain tissue. Columns of aluminum oxide were placed on columns of Amberlite CG-50 by use of a specially devised column holder so that the effluent from the upper columns could flow directly into the lower ones. Perchloric acid extracts of ...

Abstract Dividing-wall columns(DWC) are intensified distillation systems for multicomponent separations. They have the potential to save both energy and capital costs significantly than conventional simple column configurations. The several DWC columns for ternary distillations have been figured out by some creative activities from different inventors. Recently they have gained the momentum to ...

Current design practice of concrete-filled steel tube (CFST) columns uses different formulas for different section profiles to predict the axial load bearing capacity. It has always been a challenge and practically important issue for researchers and design engineers who want to find a unified formula that can be used in the design of the columns with various sections, including solid, hollow, ...

The specialized regions of neocortex of mammals, called areas, have been divided into smaller functional units called minicolumns, columns, modules, and domains. Here we describe some of these functional subdivisions of areas in primates and suggest when they emerged in mammalian evolution. We distinguish several types of these smaller subdivisions. Minicolumns, vertical arrays of neurons that ...

1 Rado showed that a rational matrix is partition regular over N if and only if it satisfies the columns 2 condition. We investigate linear algebraic properties of the columns condition, especially for oriented 3 (vertex-arc) incidence matrices of directed graphs and for sign pattern matrices. It is established that 4 the oriented incidence matrix of a directed graph Γ has the columns condition...

The axial homogeneity of preparative-scale chromatography columns was studied by measuring the overall properties of similar columns differing only by their lengths. The properties investigated were the packing density, the external porosity, the permeability and the column efficiency. Two different materials were used, one made of large, irregular silica particles compressed under either high ...

The use of tRNA affinity columns for the purification of aminoacyl-tRNA synthetases was investigated. A purification method for valyl-tRNA synthetase from Bacillus stearothermophilus is described that uses two affinity columns, one containing the pure cognate tRNA, and the other containing all tRNA species except the cognate tRNA. A method for the rapid preparation of the two columns was develo...

Coupling capillary columns in gas chromatography (GC) is not an operation that is only relevant for the users of the most advanced capillary GC methods. Simple single-column separations can also benefit from a properly selected and installed pre-column. Pre-columns connected upstream of the main column can increase the life-time of the column, efficiently refocus the analyte bands to result in ...

Monolithic columns are gaining interest as excellent substitutes to conventional particle-packed columns. These columns show higher permeability and lower flow resistance than conventional liquid chromatography columns, providing high-throughput performance, resolution and separation in short run times. Monoliths possess also great potential for the clean-up and preparation of complex mixtures....