JOURNAL OF SCIENCES (ISLAMIC AZAD UNIVERSITY)
Year:2002 | Volume:12 | Issue:45|Papers Count:11

The samples of the naphthalene sulfonation reaction mixture are analysed by HPLC. The kinetics obtained allow to suggest a model describing the evolution of the concentration. The kinetic parameters are estimated.

The protonation constants of phenylalanine and the stability constants of the complexes between dioxovanadium (V) ion and phenylalanine have been determined spectrophotometrically at 25oC and ionic strength ranging from 0.1 to 1.5 modm-3 sodium perchlorate in the pH range 1.5 - 10.5, with high ligand to metal ratios.The complexation of molybdenum (VI) with glutamic acid was investigated in aqueous solution ranging in pH from 4 to 9, using polarimetric and spectrophotometric techniques. The composition of the complex was detemined by the continuous variations method. It was shown that molybdenum (VI) forms a mononuclear 1:1 complex with glutamic acid of the type MoO3L-2 at pH 5.8. The protonation constants of glutamic acid and the stability constants of the complex were determined at 25oC and at ionic strengths ranging from (0.1 to 1.0) moldm-3 sodium perchlorate.In both complex formation reactions the dependence of the protonation and stability constants on ionic strength is described by a Debye-Huckel type equation.Finally, a comparison has been made between the patterns of ionic strength dependence for the two complexes.

In last two-decade preparation of materials by microwave irradiation became subject of interest among scientists and engineers. This method offers several advantages in comparison to conventional method including saving in time and energy. In addition, microwave irradiation is very selective in heating and consequently is very efficient in material processing relative to conventional heating. In the present study the CU2(OH)3NO3, gerhardtit, which is a precursor for the preparation of multicomponet oxide with spinel structure was prepared by microwave irradiation from mixture of aluminum nitrate and copper oxide. The effect of irradiation time and the mole ratio of substrates in the preparation of gerhardtit have been investigated. The prepared materials were characterized by X-ray powder diffraction (XRD), Scanning electron microscopy (SEM) and infrared spectroscopy (FT-IR). The results compared to the data obtained for the same material, prepared by conventional heating.

TS-2 is titanium silicate molecular sieve with MEL structure. This material has received considerable interest, because of its remarkable catalytic properties particularly in oxidation reactions under mild reaction conditions. In this paper a heterogeneous catalytic method for the oxidation of thiophene to cycloaddition of thiophene- S-oxide with thiophene -S,S-dioxide has been developed. When thiophene is treated with hydrogen peroxide in water in the presence of a large amount of TS-2, the compound 3a,4, 7, 7a-tetrahydro-4,7-epithiobenzo [b] –thiophene 1, 1,8-trioxide (I) is produced as a pure product, While in the presence of a little amount of catalyst, product (I) and 3a, 4, 7, 7a- tetrahydro-4 ,7- epithiobenzo [b] thiophene 1,8-dioxide were produced. The IR, NMR and Mass spectra of products were in good agreement with the literature data. The mechanism involves a Diels-Alder dimerization of thiophene-S-oxide followed by a further oxidation of non bridging vinylic sulfoxide in the dimmer.

The genus of Mentha is one the important of medicinal plants used in medicinal and food industries, plant materials were collected from Mentha aquatica in two different growing stage. One from before flowering (sample 1) at the beginning of June 1999 other sample from flowering stage (sample 2) at the middle of September 1999 in Cheharbagh of Gorgan (2250m) and essential oils obtaind from aerial parts of plants by steam distillation method.The oils were analyzed by capillary GC/MS. Main components from sample 1representing 79.6% of total oil were a-terpinene (25.2%), Piperitenone oxide (19.2%), 1,8-cineole (15.1%), Menthofuran (6.9%), Geranyl acetate (6.8%) and Sabinene (6.4%).Main components from sample 2 representing 86.4% of total oil were Menthofuran (45.1%), 1,8-cineole (26.6%), Menthol (8.6%) and, b-caryophyllen (6.1%).

The composition of the essential oil of the leaves of Artemisia annua L. growing wild in Iran from different locations were determined by the use of GC/MS. The leaf essential oils obtained by hydrodistilation.Predominantly comprised monoterpenoids and the main constituents were a-pinene (7.87 - 13.28%), 1.8-cineole (5.77 - 17.2%), artemisia ketone (1.44-6.67%), camphore (14.29 - 29.05%) and pinocarvone (3.43 - 8.04%).The main sesquiterpenes were b-caryphyllen (3.43 - 9.37%), germacrane - D (3.07 - 6.26%), and b-selinene (0.46 - 10.36%).

The dynamic Systems behaviours are investigating using the fourier tansform of data, the puankaveh surfaces, Iyapunov exponents calculations and attractor diemsion Study in phazzy space.At the among of mentioned methods, the Iyapunov exponents calculations are suitable method Contrary to the Iyapunov exponents Calculations for the existing equation of the behavioures of the systems, the using of the mentioned method for the laboratory investigations is very difficult. In this work, the Iynpunov exponent calculation estimated using Eckmonn method.

Optical pumping process of the Neodimium-Yag (Nd: YAG) crystals investigated by laser diodes and optimized optical absorbtion process was determined. The role of distribution of pumping source frequence and absorbtion of the crystal was investigated and also three mode of relation of pumping line spectrum and absorbtion line of crystal was analyzed. The results show that the absorbtion occure when the, frequency overlaped between the intensity distribution of the pumping source and the absorbtion spectrum of the crystal.

The need to laboratory and Computational Simulation of biological Suspensions and the microorganisntes dispersion equipment, including their advantages and disadvantages are discussed. Dispersion and evaporation of microbiological aevosols from a nazel are studied and modelled. In this regard a new computational program is presented and the results are discussed. The obtained results show that the aevosols will be evaporated after dispersion and their diameters will be reduced.By increasing nazed pressure, aerosols diameters will be reduced and their speed in air will be increased. These nazel pressure and aerosols speed are shown in model by Rinolds and Webber numbers. Increasing nazed diameter would also causes increasing Rinolds and Webber dimention less numbers.