Studies of the kinetics of ammonia decomposition on promoted nanocrystalline iron using gas phases of different nitriding degree.

Promoted nanocrystalline iron was nitrided in a differential reactor equipped with systems that made it possible to conduct both thermogravimetric measurements and hydrogen concentration analyses in the reacting gas mixture. The nitriding process, particularly catalytic ammonia decomposition reaction, was investigated under an atmosphere of ammonia-hydrogen mixtures, under atmospheric pressure. Ammonia concentrations, and so nitriding potentials, were changed gradually from 0 to 100% at the inlet of reactor.

Scavenging capacities of some thiazolyl thiazolidine-2,4-dione compounds on superoxide radical, hydroxyl radical, and DPPH radical.

The scavenging effects of eighteen thiazolyl thiazolidine-2,4-dione compounds (TTCs) on superoxide radical ( (-) (*) ) (2), hydroxyl radical HO(*), and 1,1-diphenyl-2-picrylhydrazyl (DPPH(*)) radical were evaluated by the chemiluminescence technique, electron spin resonance spectrometry (ESR) and visible spectrophotometry, respectively. The examined compounds were shown to have 27-59% ( (-) (*) ) (2) scavenging ability, 19-69% HO(*) scavenging activity and 2-32% DPPH(*) scavenging ability. This property of the tested compound seems to be important in the prevention of various diseases of free radicals etiology.

A new electrochemical method for trace water determination in methanol.

A new electrochemical method for the determination of trace water in methanol has been developed. This method is based on the effect, that a minor change in the water content affects the value of conductivity measured for dissolved in the solutions electrolyte. The conductivity measurements were performed for four inorganic salts, i.

Azo dyes decomposition on new nitrogen-modified anatase TiO2 with high adsorptivity.

New vis active photocatalyst was obtained by the modification of commercial anatase TiO2 (Police, Poland) in pressure reactor in an ammonia water atmosphere at 100 degrees C for 4h. The photocatalytic activity of new material was tested during three azo dyes decomposition: monoazo (Reactive Read), diazo (Reactive Black) and poliazodye (Direct Green). Obtained photocatalyst had new bands at 1430-1440 cm(-1) attributed to the bending vibrations of NH(4)(+) and at 1535 cm(-1) associated with NH(2) groups or NO(2) and NO.

Studies of the kinetics of two parallel reactions: ammonia decomposition and nitriding of iron catalyst.

The reaction of ammonia decomposition and nitriding reaction as an example of the parallel reactions were studied. A surface reaction was assumed as the rate limiting step. The experiments were carried out in the range of temperatures from 623 to 723 K.

Hydroxyl and superoxide radical scavenging abilities of chromonyl-thiazolidine-2,4-dione compounds.

The oxygen free radical scavenging activities of 15 chromonyl-thiazolidine-2,4-dione compounds (CTDs) were examined in chemical systems producing superoxide anion radicals, O2(-*) (potassium superoxide-18-crown-6 ether-DMSO), and hydroxyl radicals, HO(*) (a Fenton reaction: Fe(II)-H2O2-sodium trifluoroacetate, pH 6.15). Chemiluminescence and electron spin resonance (ESR) spectroscopy using 5,5-dimethyl-1-pyrroline-1-oxide (DMPO) as spin trap were applied to evaluate antioxidant behaviour of CTDs towards the oxygen radicals.

Advances in engineering of diameter and distribution of the number of walls of carbon nanotubes in alcohol CVD.

A detailed study on the influence of the substrate loading (relative to the catalyst content) and supply pressure of the feedstock on the diameter and distribution of the number of walls in carbon nanotubes in alcohol chemical vapor deposition (CVD) is presented. Here we show how one can modify the technique for the bulk formation of high quality desired nanotube types: single-walled, double-walled or multi-walled CNTs. The influence of the concentration of the catalysts with respect to the substrate concentration was examined to select the optimal conditions in terms of the sample quality.

Epoxidation of 1-butene-3-ol over titanium silicalite TS-2 catalyst under autogenic pressure.

Epoxidation of 1-butene-3-ol (1B3O) with 30 wt% hydrogen peroxide over TS-2 catalyst has been studied with methanol as a solvent and at elevated pressure (autogenic). The influence of temperature in the range of 20-120 degrees C, the molar ratio of 1B3O/H(2)O(2) 1:1-5:1, methanol concentration 5-90 wt%, TS-2 catalyst concentration 0.1-5.

Chiral recognition of Schiff bases by 15N NMR spectroscopy in the presence of a dirhodium complex. Deuterium isotope effect on 15N chemical shift of the optically active Schiff bases and their dirhodium tetracarboxylate adducts.

Optically active Schiff bases, derivatives of ortho-hydroxyaldehydes and their adducts with dirhodium tetracarboxylate complexes have been studied by (15)N NMR spectroscopy. The position of the equilibrium of Schiff bases, as well as their adducts, has been established on the basis of measurements of deuterium isotope effects on (15)N chemical shifts. At the equilibrium state, the formation of the adducts with dirhodium complexes shifted the proton-transfer equilibrium towards the NH-form.

Photodecomposition of dyes on Fe-C-TiO(2) photocatalysts under UV radiation supported by photo-Fenton process.

Fe-C-TiO(2) photocatalysts were prepared by mechanical mixing of commercial anatase TiO(2) precursor with FeC(2)O(4) and heating at 500-800 degrees C under argon flow. These photocatalysts were tested for dyes decomposition: Methylene Blue (MB), Reactive Black (RB) and Acid Red (AR). The preliminary adsorption of dyes on the photocatalysts surface was performed.

Clarification of terminological confusion concerning the crystal field quantities vs. the effective spin Hamiltonian and zero-field splitting quantities in the papers by Bayrakçeken et al. [Spectrochim. Acta Part A 66 (2007) 462 and 1291].

The physically distinct notions: crystal field (CF) [or equivalently ligand field (LF)] and effective spin Hamiltonian, which comprises zero-field splitting (ZFS) [or equivalently fine structure (FS)], are often confused each with other in literature. Confusion of the type X=Y consists in referral to the quantity Y by the name X of another well-defined quantity. Most prevailing is the CF=ZFS confusion, i.

Analysis of hemodynamics of intracranial saccular aneurysms.

The aim of this paper is to present the impact of artery curvature and neck size of aneurysms on growth rate and effectiveness of treatment of aneurysms. The dynamics of three-dimensional (3D) lateral aneurysms on arteries of different curvature were analysed using Comsol Femlab software. The simulations were performed for both steady as pulsatile flows.

Immobilization of TiO2 and Fe-C-TiO2 photocatalysts on the cotton material for application in a flow photocatalytic reactor for decomposition of phenol in water.

TiO2 and Fe-C-TiO2 photocatalysts have been immobilized on the cotton material and used in a flow photocatalytic reactor for phenol decomposition. The cotton material has been applied as a support for photocatalyst, because can be easily removed and replaced in a reactor, what facilitates the performance of the photocatalytic process. Fe-C-TiO2 photocatalyst has been prepared by modification of TiO2 fine particles of anatase structure with FeC2O4 through heating in Ar at 500 degrees C.

Chiral recognition of the Schiff bases by NMR spectroscopy in the presence of a chiral dirhodium complex. Deuterium isotope effect on 13C chemical shift of the optically active Schiff bases and their dirhodium adducts.

The dirhodium method has been successfully applied in chiral recognition of the optically active Schiff bases, derivatives of ortho-hydroxyaldehydes existing in the NH-form. or at tautomeric equilibrium. The position of the equilibrium of Schiff bases as well as their adducts has been established on the basis of measurements of deuterium isotope effects on 13C chemical shifts.

In vitro scavenging activity for reactive oxygen species by N-substituted indole-2-carboxylic acid esters.

The hydroxyl radical (HO*)- and superoxide anion radical (O* (2))-scavenging activity, as well as the singlet oxygen ((1)O(2))-quenching property of N-substituted indole-2-carboxylic acid esters (INDs) were investigated by deoxyribose degradation assay, a chemiluminescence method and the electron spin resonance (ESR) spin-trapping technique. This novel group of compounds was developed as a search for cyclooxygenase-2 (COX-2)-selective enzyme inhibitors. The results obtained demonstrated that of the 16 compounds examined, five inhibited light emission from the superoxide anion radical (O* (2))-DMSO system by at least 60% at a concentration of 1 mmol/L, nine prevented the degradation of deoxyribose induced by the Fenton reaction system (range 3-78%) or scavenged hydroxyl radicals (HO*) directly (range 8-93%) and 14 showed the (1)O(2)-quenching effect (range 10-74%).

Long-range deuterium isotope effects on (13)C chemical shifts of intramolecularly hydrogen-bonded N-substituted 3-(cycloamine)thiopropionamides or amides: a case of electric field effects.

A series of intramolecularly hydrogen-bonded N-substituted 3-(piperidine, morpholine, N-methylpiperazine)thiopropionamides and some corresponding amides have been studied with special emphasis on hydrogen bonding. The compounds have been selected in order to vary and to minimize the N..

Influence of an adjuvant on the distribution of herbicides in a sediment/water system.

This study concerned the influence of a mineral oil adjuvant used as tank-mix, on the sorption of commercially formulated compounds in soil using a laboratory-scale sediment/water system. The laboratory experiment was conducted with the adjuvant Atpolan 80 EC and the triazine herbicide atrazine and isoxaflutole which belong to the isoxazole class of herbicides. Ditch bed sediment was the medium.

Preparation and bioactivity of novel multiblock thermoplastic elastomer/tricalcium phosphate composites.

There is a recognized need for improved treatment of osteoarthritis of the finger joints disease. Joint fusions are commonly used for treating the pain and potential deformity of arthritis. At severe deformity, artificial joint replacement is required.

Application of carbon-coated TiO2 for decomposition of methylene blue in a photocatalytic membrane reactor.

An application of carbon-coated TiO(2) for decomposition of methylene blue (MB) in a photocatalytic membrane reactor (PMR), coupling photocatalysis and direct contact membrane distillation (DCMD) was investigated. Moreover, photodegradation of a model pollutant in a batch reactor without membrane distillation (MD) was also examined. Carbon-modified TiO(2) catalysts containing different amount of carbon and commercially available TiO(2) (ST-01) were used in this study.

Slow polarization relaxation in non-uniform telluric acid ammonium phosphate crystals.

The characteristic features of polarization and spontaneous depolarization kinetics in non-uniform telluric acid ammonium phosphate (TAAP) crystals are investigated by observation of the domain structure using a nematic liquid crystal method. We present experimental results showing the correlation between the internal bias field, responsible for the offset of the hysteresis loop and the backswitching process. The internal field caused by structural disorder accounts for a broad spectrum of energy barriers for domain nucleation.

Special applications of fluorinated organic compounds.

The applications of fluorinated organic compounds (FOCs) as finishing agent for fabrics, components of extinguishing agents, electroplating bathes, lubricating oils, oxygen carriers in blood substitutes have been discussed. Recent achievements in methods of the fluorination and general principles of the synthesis of useful perfluorinated organic compounds are given as well.

Deuterium isotope effect on 13C chemical shifts of tetrabutylammonium salts of Schiff bases amino acids.

Deuterium isotope effects on 13C chemical shift of tetrabutylammonium salts of Schiff bases, derivatives of amino acids (glycine, L-alanine, L-phenylalanine, L-valine, L-leucine, L-isoleucine and L-methionine) and various ortho-hydroxyaldehydes in CDCl3 have been measured. The results have shown that the tetrabutylammonium salts of the Schiff bases amino acids, being derivatives of 2-hydroxynaphthaldehyde and 3,5-dibromosalicylaldehyde, exist in the NH-form, while in the derivatives of salicylaldehyde and 5-bromosalicylaldehyde a proton transfer takes place. The interactions between COO- and NH groups stabilize the proton-transferred form through a bifurcated intramolecular hydrogen bond.

Adsorption dynamics of chlorinated hydrocarbons from multi-component aqueous solution onto activated carbon.

The results and a numerical simulation of studies on dynamics of the adsorption from seven-component aqueous solution of light chlorinated hydrocarbons on activated carbon have been presented. Aqueous solution of 1,2-dichloroethane (12DCE), 1,1,2,2-tetrachloroethane (S-TET), chloroform (CHCl(3)), carbon tetrachloride (CCl(4)), 1,1-dichloroethene (VDC), perchloroethene (PER) and 1,1,2-trichloroethene (TRI) was used. Concentrations of chlorohydrocarbons were similar as in wastewater from vinyl chloride plant.

Diffraction of a Gaussian beam in a three-dimensional smoothly inhomogeneous medium: an eikonal-based complex geometrical-optics approach.

We present an ab initio account of the paraxial complex geometrical optics (CGO) in application to scalar Gaussian beam propagation and diffraction in a 3D smoothly inhomogeneous medium. The paraxial CGO deals with quadratic expansion of the complex eikonal and reduces the wave problem to the solution of ordinary differential equations of the Riccati type. This substantially simplifies the description of Gaussian beam diffraction as compared with full-wave or parabolic (quasi-optics) equations.