On the adsorption and diffusion of Methylene Blue in glass fibers

The adsorption and diffusion phenomena of Methylene Blue dye on glass fiber have been explored. Both isotherm and kinetics have been studied. Effect of process parameters such as pH, adsorbent loading, and initial dye concentration was investigated. Temperature had a little effect on adsorption. A diffusion model was developed to estimate the diffusivity of the dye in glass fiber. The diffusivity was found to be varying exponentially with the dye concentration.     

Novel synthesis of isoquinolines using isobenzofuran-nitrile Diels-Alder reactions

[reaction: see text] The synthesis of isoquinolines through coupling of 2-alkynylbenzaldehyde derivatives with beta-cyanocarbene complexes has been examined. The reaction involves formation of an isobenzofuran followed by intramolecular Diels-Alder reaction with the nitrile, a process with limited precedent. The unique success of this process in this system has been attributed to deoxygenation of the initial adduct to form the isoquinoline ring system.     

Applicability of equilibrium and kinetic models on the herbicide 4-chloro-2-methyl phenoxyacetic acid adsorption on bituminous shale

Adsorption characteristics of herbicide 4-chloro-2-methylphenoxyacetic acid (MCPA) have been evaluated using bituminous shale (BS) as a model adsorbent-containing solid organic matter in a mineral matrix. The adsorption of MCPA on BS has been studied with varying concentration, temperature, pH and contact time, using batch technique. Adsorption ability of BS increases with increasing temperature and decreasing pH in the studied concentration range of (0.6–4.0) × 10⁻⁴ M. Theoretical curves calculated from Freundlich, Dubinin-Radushkevich (D-R), Langmuir and Temkin isotherm equations show a two-step isotherm shape. The results could be explained by assuming the presence of two-type sites with different affinity on adsorbent surface. Adsorption process is endothermic and entropy controlled at the first stage, and exothermic and enthalpy controlled at the second stage. The mechanism proposed based on surface ionization and complexation model is consistent with the pH dependent experimental results. Kinetic data fit well to both Paterson’s and Nernst Planck model based on homogeneous solid phase diffusion (HSPD). The values of particle diffusion coefficients (D _p ) predicted from both models are comparable each other and independent of temperature and concentration.      

Hydroxyapatite coating on stainless steel pre-coated with bovine serum albumin at ambient conditions

A biomimetic process for coating of nanosized hydroxyapatite on stainless steel, which capitalises the dual nature of the protein bovine serum albumin in both metal binding and a strong affinity for calcium ions, has been developed. The novelty of the process lies in pre-conditioning the metallic surface using the above protein prior to its mineralization with hydroxyapatite at ambient conditions. The microporous morphology of these coatings may provide favourable solubility and resorbability as desired by many orthopaedic and orthodontic applications.     

K-capture probability in the decay of139Ce(137.5d)

The K-capture probability (P _K) in the decay of¹³⁹Ce (137.5d) has been determined from the analysis of the K x-ray gamma ray sum-peak observed with a Ge (Li) x-ray detector. Furthermore,P _K is estimated independently from the measurement of the K x-ray intensity in the decay, using the known conversion coefficients of the 165.8 keV transition. Using the weighted average ofP _K measured as above, the mass difference between¹³⁹Ce and¹³⁹La is found to be 273 _?13 ⁺²¹ keV.     

Triphenylpyridine-based star-shaped π-conjugated oligomers with triphenylamine core: synthesis and photophysical properties

Two novel star-shaped π-conjugated oligomers bearing a triphenylpyridine moiety as peripheral units and triphenylamine as a core have been synthesized via the threefold Heck/Sonogoshira coupling reaction protocol and their absorption and fluorescence properties have been examined. These oligomers showed excellent solubility in common organic solvents, emit light in blue and violet regions, and have high thermal stability.     

Pyridine-cored V-shaped π-conjugated oligomers: synthesis and optical properties

A new series of V-shaped pyridine-cored π-conjugated oligomers are synthesized utilizing two-fold Heck/Suzuki coupling reactions. Optical properties of these compounds (λ_max=390–449 nm, Φ_fl=79–5%, in solutions) are discussed. They are shown to be thermally stable and soluble in common organic solvents. Stilbenoid oligomers exhibited much higher fluorescence quantum yields than tri- and tetra-phenylethylene substituted oligomers in solutions.