Combining rule for interaction energies of the (CO)2, (N2)2 and CO-N2 complexes

The relationship between interaction energies of the most stable structures of the (CO)₂, (N₂)₂ and CO-N₂ complexes is investigated using the supermolecule CCSD(T) and MP4 methods and aug-cc-pVXZ (X = D,T,Q) basis sets extended by a set of midbond functions centred in the middle of the intermolecular bond. A simple combining rule for interaction energies of this triad of clusters is proposed.     

Cartesian Dynamics of Simple Molecules X Linear Quadratomics (C∞v Symmetry)

The vibrations of linear ABC₂ type molecules with C_∞V point group are analysed in terms of Cartesian co-ordinates. Algebraic expressions for the three stretching and two bending normal mode frequencies are derived in terms of longitudinal and transverse force constants, atomic masses and bond lengths. Values of non-valence interaction parameters are transferred from A₂B₂ (D_∞h) molecules, and values of the principal force constants are adjusted to reproduce the observed frequencies for a number of asymmetric halogen derivatives of acetylene. Normal mode frequencies of various isotopic species are also calculated. The nature of the computed eigenvectors for these molecules is briefly discussed. It is found that the carbon-carbon and carbon-hydrogen valence interactions remain approximately constant for these molecules, whereas the carbon-halogen bonds show a weakening trend with increasing halogen mass.     

Superconducting composites: Calculation of the localized single-particle excitations

The problem of localized single-particle excitations for the geometry of a superconducting sphere embedded in another superconductor has been investigated. Assuming constant order parameters in both materials Bogoliubov equations are solved for the s-state. The dependence of the excitation energy on the particle size and the ratio of the order parameters is shown.     

Bivariate inverse gaussian distribution

Summary A bivariate inverse Gaussian (IG) density function is constructed. Relations of the bivariate IG distribution to the normal and χ² distributions are established. The corresponding bivariate random walk (RW) density function is obtained. The properties and behaviour of bivariate IG distribution are studied for large parametric values. Moment estimates of the five parameters are given and applications are pointed out. A generalization to the multivariate IG distribution is proposed.     

ADSORPTION DYNAMICS OF MACROPOROUS POLYMERIC ADSORBENT Ⅱ. The Studies on the Film Diffusion Mass-Transfer Process

1 INTRODUCTIONAt present time, most of the studies for the adsorption dynamics of macroporous adsorbent,.especially for the film diffusion mass-transfer process, were based on the conclusions for theBoyd ion-exchange dynamics equationl'l. The structure of gel-type ion-exchange resin andmacroporous polystyrene resin is different. Because of having the hydrophilic group, both of theirmer and outer of the ion-exchange resin can swell to the reticulation struCture in the aqueous.Based on the…     

Solid–solid interactions between ferric and cobalt oxides as influenced by Al2O3-doping

The solid–solid interactions between pure and alumina-doped cobalt and ferric oxides have been investigated using DTA, IR and XRD techniques. Equimolar proportions of basic cobalt carbonate and ferric oxide and different amounts of aluminum nitrate were added as dopant substrate. The amounts of dopant were 0.75, 1.5, 3.0 and 4.5 mol% Al₂O₃.

The results obtained revealed that solid–solid interaction between Fe₂O₃ and Co₃O₄ takes place at temperatures starting from 700°C to produce cobalt ferrite. The degree of propagation of this reaction increases progressively as a function of precalcination temperature and Al₂O₃-doping of the reacting solids. However, the heating of pure mixed solids at 1000°C for 6 h. was not sufficient to effect the complete conversion of the reacting solids into CoFe₂O₄, while the addition of a small amount of Al₂O₃ (1.5 mol%) to ferric/cobalt mixed solids followed by precalcination at 1000°C for 6 h conducted the complete conversion of the reacting solids into cobalt ferrite. The heat treatment of pure and the 0.75 mol%-doped solids at 900 and 1000°C effected the disappearance of most of IR transmission bands of the free oxides with subsequent appearance of new bands characteristic for the CoFe₂O₄ structure. An increase in the amount of Al₂O₃ added from 1.5–4.5 mol% to the mixed solids precalcined at 1000°C led to the disappearance of all bands of free oxides and appearance of all bands of cobalt ferrite. The promotion effect of Al₂O₃ in cobalt ferrite formation was attributed to an effective increase in the mobility of the various reacting cations. The activation energy of formation (ΔE) of CoFe₂O₄ phase was determined for pure and doped solids. The computed values of ΔE were, respectively, 99.6, 87.8, 71.9, 64.7 and 48.7 kJ mol⁻¹ for the pure solid and those treated with 0.75, 1.5, 3 and 4.5 mol% Al₂O₃.     

Photocatalysis of β-blockers – An overview

Photocatalysis is one of the most effective advanced oxidation processes to remove residual pharmaceuticals from the aquatic environment. β-Blockers are the group of pharmaceuticals commonly found in the environment and are showing potential risk to the aquatic and terrestrial organisms. This paper provides an overview of different photocatalytic procedures found in the literature for the abatement of β-blockers.     

Manufacturing cell formation by state-space search

This paper addresses the problem of grouping machines in order to design cellular manufacturing cells, with an objective to minimize inter-cell flow. This problem is related to one of the major aims of group technology (GT): to decompose the manufacturing system into manufacturing cells that are as independent as possible. This problem is NP-hard. Thus, nonheuristic methods cannot address problems of typical industrial dimensions because they would require exorbitant amounts of computing time, while fast heuristic methods may suffer from poor solution quality. We present a branch-and-bound state-space search algorithm that attempts to overcome both these deficiencies. One of the major strengths of this algorithm is its efficient branching and search strategy. In addition, the algorithm employs the fast Inter-Cell Traffic Minimization Method to provide good upper bounds, and computes lower bounds based on a relaxation of merging.This work was supported in part by NSF Grants DDM-9201779, IRI-9306580, and NSFD EEC 94-02384 in the US, and the CMDS project (work order 019/7-148/CMDS-1039/90-91) in India. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.     

Contour line construction for a new rectangular facility in an existing layout with rectangular departments

In a recent paper, Savas et al. [S. Savas, R. Batta, R. Nagi, Finite-size facility placement in the presence of barriers to rectilinear travel, Operations Research 50 (6) (2002) 1018–1031] consider the optimal placement of a finite-sized facility in the presence of arbitrarily shaped barriers under rectilinear travel. Their model applies to a layout context, since barriers can be thought to be existing departments and the finite-sized facility can be viewed as the new department to be placed. In a layout situation, the existing and new departments are typically rectangular in shape. This is a special case of the Savas et al. paper. However the resultant optimal placement may be infeasible due to practical constraints like aisle locations, electrical connections, etc. Hence there is a need for the development of contour lines, i.e. lines of equal objective function value. With these contour lines constructed, one can place the new facility in the best manner. This paper deals with the problem of constructing contour lines in this context. This contribution can also be viewed as the finite-size extension of the contour line result of Francis [R.L. Francis, Note on the optimum location of new machines in existing plant layouts, Journal of Industrial Engineering 14 (2) (1963) 57–59].     

Cleaning time and fate of phosphoric acid as conditioning agent on human dental enamel and dentin. An in vitro radiotracer study

In this study the cleaning time and fate of phosphoric acid on human dental enamel and dentin has been investigated, using the radioactive tracer technique with³²P as an indicator of phosphorus. Twenty seconds were found to be sufficient for cleaning the enamel from phosphoric acid, which is used for conditioning, and from formulations produced from its interaction with enamel. It was also found that dentin protection is necessary before conditioning with phosphoric acid due to the retention penetration of the latter through subsurface dentinal tubules. In addition, there seems to be an interaction between phosphoric acid and Ca(OH)₂ leading to the formation of a sparingly soluble compound.