The emission spectrum of bismuth monofluoride BiF—‘A’ system

The observation of (A-X) system of BiF has been extended up to λ 5316 and twenty new bands belonging to this system have been recorded. The band heads could be represented by the following equation: {Mathematical expression} Seven other faint bands in the region λ 5316-5492 have also been reported, which, however, could not be classified. By our analysis of the present data and from known thermochemical data it has been deduced that the ground state dissociation energy is, in all probability, around 20000 cm.-1 (∼2·5 ev.) and that the dissociation products are the normal Bi and F atoms. The dissociation energy of the upper state and the correlation rules have been used to show that the dissociation products in the upper state are very likely to be Bi atom in the excited state2D3/2 and F atom in its ground state (2P3/2).

Vibrational analysis of the (B2P{cyrillic}→X2P{cyrillic}) system of NS

A few red degraded bands attributable to NS have been reported earlier by Fowler and Barker, Dressler and Barrow et al, and they occur in the same region (2300 to 2700 Å) as the bands of the known systems (C2∑+-X2P{cyrillic}) and (A2Δ-X2P{cyrillic}). Measurements made on the heads of some of these weak bands led Barrow et al. to believe that these bands may form a system analogous to the β-system of NO and be due to a2P{cyrillic}-2P{cyrillic} transition. The spectrum of NS has now been studied in a little more detail by means of an uncondensed discharge through dry nitrogen and sulphur vapour in the presence of argon and thirty three bands belonging to this system have been recorded in the region 2280 to 2760 Å. It has been found possible to represent the band heads by means of the equation {Mathematical expression}. Taking the lower state doublet interval as 223 cm-1, it is shown that the separation in the upper state is 94 cm-1. The ratio of the force constants in the upper and the ground states is found to be 0·39 and is nearly the same as that in the β-system of NO (0·30). The present vibrational analysis therefore supports the view that these new red degraded bands of NS arise from a (B2P{cyrillic}→X2P{cyrillic}) transition and the observed intensity distribution in the form of a wide parabola is also in qualitative agreement with what is expected from the moderately large Δ re (∼0·12Å) value.

The emission spectrum of bismuth bromide (BiBr)-"A" system

The emission spectrum of bismuth monobromide has been investigated and a vibrational analysis of the A→X system has been made. About 286 bands were recorded in the region λλ 4595–6063 and the isotope effect due to Br79 and Br81 was observed in about 87 bands. A value of 2·74 ev. for the dissociation energy of the excited state has been obtained and arguments have been given to show that the dissociation products in the excited state are Bi(4S3/2) and Br(2P3/2) and that those of the ground state are most probably Bi (4S3/2) and Br (2P1/2) atoms.

A Geometric Algorithm for Learning Oblique Decision Trees

In this paper we present a novel algorithm for learning oblique decision trees. Most of the current decision tree algorithms rely on impurity measures to assess goodness of hyperplanes at each node. These impurity measures do not properly capture the geometric structures in the data. Motivated by this, our algorithm uses a strategy, based on some recent variants of SVM, to assess the hyperplanes in such a way that the geometric structure in the data is taken into account. We show through empirical studies that our method is effective.

Dual-Drug Delivery System Based on In Situ Gel-Forming Nanosuspension of Forskolin to Enhance Antiglaucoma Efficacy

The present study was designed to improve the bioavailability of forskolin by the influence of precorneal residence time and dissolution characteristics. Nanosizing is an advanced approach to overcome the issue of poor aqueous solubility of active pharmaceutical ingredients. Forskolin nanocrystals have been successfully manufactured and stabilized by poloxamer 407. These nanocrystals have been characterized in terms of particle size by scanning electron microscopy and dynamic light scattering. By formulating Noveon AA-1 polycarbophil/poloxamer 407 platforms, at specific concentrations, it was possible to obtain a pH and thermoreversible gel with a pH(gel)/T-gel close to eye pH/temperature. The addition of forskolin nanocrystals did not alter the gelation properties of Noveon AA-1 polycarbophil/poloxamer 407 and nanocrystal properties of forskolin. The formulation was stable over a period of 6 months at room temperature. In vitro release experiments indicated that the optimized platform was able to prolong and control forskolin release for more than 5 h. The in vivo studies on dexamethasone-induced glaucomatous rabbits indicated that the intraocular pressure lowering efficacy for nanosuspension/hydrogel systems was 31% and lasted for 12 h, which is significantly better than the effect of traditional eye suspension (18%, 4-6 h). Hence, our investigations successfully prove that the pH and thermoreversible polymeric in situ gel-forming nanosuspension with ability of controlled drug release exhibits a greater potential for glaucoma therapy.

A neural network based CBIR system using STI features and relevance feedback

Multimedia mining primarily involves, information analysis and retrieval based on implicit knowledge. The ever increasing digital image databases on the Internet has created a need for using multimedia mining on these databases for effective and efficient retrieval of images. Contents of an image can be expressed in different features such as Shape, Texture and Intensity-distribution(STI). Content Based Image Retrieval(CBIR) is an efficient retrieval of relevant images from large databases based on features extracted from the image. Most of the existing systems either concentrate on a single representation of all features or linear combination of these features. The paper proposes a CBIR System named STIRF (Shape, Texture, Intensity-distribution with Relevance Feedback) that uses a neural network for nonlinear combination of the heterogenous STI features. Further the system is self-adaptable to different applications and users based upon relevance feedback. Prior to retrieval of relevant images, each feature is first clustered independent of the other in its own space and this helps in matching of similar images. Testing the system on a database of images with varied contents and intensive backgrounds showed good results with most relevant images being retrieved for a image query. The system showed better and more robust performance compared to existing CBIR systems

Synthesis and structural aspects of quasicrystals in Mg-Al-Ag system: Mg4Al6Ag

The existence of an icosahedral phase in Mg−Al−Ag is better understood on a crystallographic basis rather than on a quantum structural diagram basis. The quasicrystalline structure is delineated in terms of quasiperiodic arrangement of Pauling triacontahedra, which can be identified in the equilibrium structure. Subtle differences in the electron diffraction patterns have been recorded compared to the ideal quasicrystalline pattern. The misalignment of spots and distortions are better attributed to higher order rational approximate structure than anisotropic phason strain. Ares of diffuse intensity have been related to the ordering among the atoms in the clusters.

Experimental and Computational Characterization of Alloy--Spinel--Corundum Equilibrium in the System Fe--Co--Al--O at 1873K

The three-phase equilibrium between alloy, spinel solid solution and alpha -Al sub 2 O sub 3 in the Fe--Co--Al--O system at 1873k was fully characterized as a function of alloy composition using both experimental and computational methods. The equilibrium oxygen content of the liquid alloy was measured by suction sampling and inert gas fusion analysis. The O potential corresponding to the three-phase equilibrium was determined by emf measurements on a solid state galvanic cell incorporating (Y sub 2 O sub 3 )ThO sub 2 as the solid electrolyte and Cr + Cr sub 2 O sub 3 as the reference electrode. The equilibrium composition of the spinel phase formed at the interface between the alloy and alumina crucible was measured by electron probe microanalysis (EPMA). The experimental results were compared with the values computed using a thermodynamic model. The model used values for standard Gibbs energies of formation of pure end-member spinels and Gibbs energies of solution of gaseous O in liquid Fe and cobalt available in the literature. The activity--composition relationship in the spinel solid solution was computed using a cation distribution model. The variation of the activity coefficient of O with alloy composition in the Fe--Co--O system was estimated using both the quasichemical model of Jacob and Alcock and Wagner's model along with the correlations of Chiang and Chang and Kuo and Chang. The computed results of spinel composition and O potential are in excellent agreement with the experimental data. Graphs. 29 ref.--AA

An investigation of the PrBa2Cu3O7-δ system

Members of the PrBa2Cu3O7–delta system possessing the orthorhombic structure over a wide range of oxygen stoichiometry (delta=–0.5 to +0.5) have been prepared and characterized. Similar compositions with a tetragonal structure have also been prepared. None of the oxides is superconducting, independent of the structure or stoichiometry. Praseodymium seems to be present to a small extent in the 4+ state in oxygen-excess (negative delta) samples. Orthorhombic PrBa2Cu3O7–delta samples show the presence of twins suggesting that twins arise from orthorhombicity and have no relation to the superconductivity. A neutron diffraction study of a near-stoichiometric sample has shown a disordered orthorhombic structure with 72% occupancy of the 01 (chain) sites and with no interchange between Pr and Ba sites.

Design and fabrication of an automated temperature programmed reaction system to evaluate 3-way catalysts Ce1-x-y(La/Y)(x)PtyO2-delta

A completely automated temperature-programmed reaction (TPR) system for carrying out gas-solid catalytic reactions under atmospheric flow conditions is fabricated to study CO and hydrocarbon oxidation, and NO reduction. The system consists of an all-stainless steel UHV system, quadrupole mass spectrometer SX200 (VG Scientific), a tubular furnace and micro-reactor, a temperature controller, a versatile gas handling system, and a data acquisition and analysis system. The performance of the system has been tested under standard experimental conditions for CO oxidation over well-characterized Ce1-x-y(La/Y)(y)O2-delta catalysts. Testing of 3-way catalysis with CO, NO and C2H2 to convert to CO2, N-2 and H2O is done with this catalyst which shows complete removal of pollutants below 325 degrees C. Fixed oxide-ion defects in Pt substituted Ce1-y(La/Y)(y)O2-y/2 show higher catalytic activity than Pt ion-substituted CeO2

Biotransformations of α-terpineol in the rat: Its effects on the liver microsomal cytochrome P-450 system

Alpha-Terpineol (I), a monocyclic monoterpene tertiary alcohol, is widely used in the manufacture of perfumes, cosmetics, soaps and antiseptic agents. It was reported earlier (Horning et al. 1976) that this monoterpene alcohol when administered to humans is hydroxylated to p-menth-l,2,8-triol (II). It is not known whether c~-terpineol also produces other metabolites during its metabolism in the mammalian system and if so, the nature of these metabolites.

Interdiffusion Study in the Fe-Nb System

The diffusion characteristics of the Fe-Nb system were investigated using the diffusion couple technique. The average interdiffusion coefficient was calculated for the Fe2Nb Laves and the FeNb mu phases.The possible diffusion mechanism was predicted by using the calculated values of the activation energy for diffusion. Kirkendall marker experiments were conducted to determine the relative mobilities of the species. Fe was found to have a faster diffusion rate than Nb in both phases.

CHITRA: Cognitive handprinted input-trained recursively analyzing system for recognition of alphanumeric characters

A novel system for recognition of handprinted alphanumeric characters has been developed and tested. The system can be employed for recognition of either the alphabet or the numeral by contextually switching on to the corresponding branch of the recognition algorithm. The two major components of the system are the multistage feature extractor and the decision logic tree-type catagorizer. The importance of ldquogoodrdquo features over sophistication in the classification procedures was recognized, and the feature extractor is designed to extract features based on a variety of topological, morphological and similar properties. An information feedback path is provided between the decision logic and the feature extractor units to facilitate an interleaved or recursive mode of operation. This ensures that only those features essential to the recognition of a particular sample are extracted each time. Test implementation has demonstrated the reliability of the system in recognizing a variety of handprinted alphanumeric characters with close to 100% accuracy.

Indications of superconductivity in the 200–300K range in the Bi-Ca-Sr-Cu-O system

Some of the Bi-Ca-Sr-Cu-O compositions show indications of onset of superconductivity in the 200–300 K region, possibly due to the intergrowth of different layered sequences.