Volume 16, No. 2 (2015)
Articles
EFFECTS OF SIMPLIFIED CHEMICAL KINETIC MODEL ON THE MICRO-FLAME STRUCTURE AND TEMPERATURE OF THE LEAN PREMIXED METHANE-AIR MIXTURES
JUNJIE CHEN(*), XUHUI GAO
The effect of simplified chemical kinetic model on the micro-flame structure, central axis and wall temperatures were investigated with different one-step global chemical kinetic mechanisms following Mantel, Duterque and Fernández-Tarrazo models. Numerical investigations of the premixed methane-air flame in the micro-channel and lean conditions were carried out to compare and analyze the effect of the comprehensive chemical kinetic mechanisms. The results indicate that one-step global chemical kinetic mechanism affects both the micro-flame shape and the combustion temperature. Among three simulation models, Mantel model allows a stable micro-flame with a bamboo shoot form, which anchor at the inlet. Duterque model gives a stable elongated micro-flame with a considerable ignition delay, and a dead zone with fluid accumulation is observed at the entrance, which may explain the very high combustion temperature and the fast reaction rate obtained, despite the micro-flame development presents a very hot spot and causes a broadening of the combustion zone. Fernández-Tarrazo model results in a rapid extinction and doesn't seem to take all the kinetic behavior into account for the appropriate micro-combustion simulations.
R2NH2C2O4SnC2O4SnBu3, (R2NH2)4(C2O4)3(SnR’3)2 (R = Cy, i-Bu; R’ = Me, Bu) AND SOME MIXED ORGANO- AND HALOTIN (IV) OXALATO NEW MOETIES CONTAINING COMPLEXES: SYNTHESIS, INFRARED, MOSSBAUER AND NMR STUDIES
YAYA SOW, LIBASSE DIOP(*)
On allowing (Cy2NH2)2C2O4∙2H2O to react with SnBu3Cl or SnMe3Cl, i-Bu2NH2HC2O4 with SnBu3Cl, (Bu2NH2)2C2O4 with SnMe3Cl, (i-Bu2NH2)2C2O4 with SnPh2Cl2, a mixture of i-Bu2NH2)2C2O4 and (Me4N)2C2O4 with SnPh2Cl2, (Pr2NH2)2C2O4 with SnPh3Cl, the oxalato derivatives and complexes Cy2NH2C2O4SnBu3.3H2O∙1/4Cy2NH2Cl, i-Bu2NH2C2O4SnBu3∙1/2(i-Bu2NH2)2C2O4,y2NH2C2O4SnMe3∙1/2(Cy2NH2)2C2O4, Sn(C2O4)2∙[C2O4(SnMe3∙H2O)2]∙2EtOH∙1/4[(Bu2NH2)2C2O4],(i-Bu2NH2)2 C2O4∙ 2SnPh2Cl2∙SnCl4∙4(i-Bu2NH2OH)∙2(i-Bu2NH2Cl), 2[SnPh2Cl4(i-Bu2NH2)2]∙ SnCl2C2O4∙4i-Bu2NH2Cl and 2[Pr2NH2C2O4SnPh3]∙(Pr2NH2)2C2O4∙SnCl4∙ 2Pr2NH2Cl were obtained. Double chain, two metallic components and a dimeric structures are suggested with trans coordinated SnMe3 residues, these chains being connected through R2NH2+ (R = Cy, i-Bu) only or by (R2NH2)2C2O4 bridges. The oxalate behaves as a monochelating, a bridging, an only hydrogen bonding involved or monodentate and H bond involved ligand. The environments around the tin (IV) centres are cis or trans trigonal bipyramidal, tetrahedral or octahedral. Supramolecular architectures may be obtained when extra hydrogen bonds are possible.
PHYSICOCHEMICAL AND BIOCHEMICAL PROPERTIES OF HONEY BEE PRODUCTS IN SOUTH ALGERIA
ABDELKRIM REBIAI(*), TOUHAMI LANEZ, ATEF CHOUIKH
The aim of the present study was to characterize the physical, biochemical and antioxidant properties of south Algeria honey samples (n = 5). Physical parameters, such as pH, moisture content, electrical conductivity, total dissolved solids, color intensity, total sugar content were measured. Several biochemical and antioxidant tests were performed to determine the antioxidant properties of the honey samples. The mean pH was 4.54, and moisture content was 14.88 %. The mean electrical conductivity was 0.597 mS∙cm-1, and the mean total dissolved solid was 0.14 % and the mean color was 163.6 mm Pfund. The mean total sugar contents was 82.76 %. High mean values of phenolic and flavonoid contents were respectively 697.22 mg GAE∙kg-1 and 290.70 mgREE∙kg-1. Antioxidant activity was also measured using DPPH assays, value of 26.19 mg∙mL-1 was detected for south Algeria (El-Oued) honey.
INVESTIGATION OF THE REDUCTION OF BENZOIN WITH Ni-Al ALLOY IN AQUEOUS ALKALI MEDIUM </br> INVESTIGATION DE LA REDUCTION DE LA BENZOÏNE AVEC ALLIAGE Ni-Al DANS UN MILIEU AQUEUX ALCALIN
MIRELA SUCEVEANU(1*), ADRIANA FINARU(1), SORIN I. ROSCA(2)
The paper aims to elaborate a methodology for establishing the structure and sterical configuration of reduction products with the system Ni-Al/NaOH/H2O by using spectroscopic methods (mainly 1H-NMR) and method of coupling gas chromatography with mass spectrometry (GC-MS). In case of benzoin, the compositional analysis for reduction products was made by gas chromatographic methods (GC) with FID detection. The quantitative analysis was based on the value of integrals of the relevant signals in the 1H-NMR spectrum of the crude reaction product. The 13C-NMR and FTIR spectra provided the necessary information to confirm the quality of the composition of the reaction product.
NEW ORGANO-AND HALOTIN (IV) WITH EDTA: SYNTHESIS AND INFRARED STUDY
SERIGNE CISSE, IBRAHIMA CISSE, LIBASSE DIOP(*)
Nine acidic or neutral ethylenediaminetetraacetato [H2Y2-, H3Y- or Y4-] containing adducts and derivatives have been synthesized and studied by infrared. The suggested structures are discrete with octahedral or trigonal bipyramidal environments around the tin centres, the ethylenediaminetetraacetic anion behaving as a bidentate and hydrogen bonds involved, a tridentate, a tetradentate, a bichelating and hydrogen bonds involved ligand, a tri- or tetrachelating ligand. For all the structures when intermolecular hydrogen bonds involving OH or CH groups are considered, a supramolecular architecture may be obtained.
DEVELOPMENT OF CYCLIC VOLTAMMETRIC METHOD FOR THE STUDY OF THE INTERACTION OF ANTIOXIDANT STANDARDS WITH SUPEROXIDE ANION RADICALS CASE OF α-TOCOPHEROL
TOUHAMI LANEZ(*), MERIEM HENNI, HADIA HEMMAMI
This work aims to develop a cyclic voltammetry based assay for the calculation of binding parameters like binding constant, ratio of binding constants, and binding free energy of the free and superoxide anion radical bound forms of α-tocopherol (TOC) antioxidant standard. The determination of binding constant is based upon the decrease in anodic peak current of the redox couple in the presence of antioxidant standard, whereas the mode of interaction is concluded from the shift in peak potential values. The diffusion coefficients of both free superoxide anion radical and its bounded forms with TOC were also evaluated from Randles-Sevcik equation.
STUDY CONCERNING THE PRODUCTION OF BIOMASS PROTEIN BY VALORISATION OF BY-PRODUCTS FROM THE DAIRY INDUSTRY </br> ETUDE CONCERNANT L’OBTENTION DE BIOMASSE PROTEIQUE PAR VALORISATION DES SOUS-PRODUITS DE L’INDUSTRIE LAITIERE
LUMINITA GROSU(*), IRINA-CLAUDIA ALEXA, OANA-IRINA PATRICIU
The development of the food industry ensures the necessary protein for the population and in this perspective the valorisation of by-products from the dairy industry (whey and buttermilk) can be a solution in this direction. Whey is a very important substrate for the biosynthesis of single cell protein by its lactose content which is the main source of fermentable substrate for yeasts. As part of our research, the biomass protein was obtained using whey as source of lactose and other sugars and yeast strains of Candida utilis. The modelling program used is 2nd order system centred with three variables: amount of sugar, amount of nitrogen and quantity of phosphorus. The following parameters have been pursued: biomass content, yield of sugar consumption and protein content. The process conditions are influenced by the addition of different nutrients.
SYNTHESIS AND CRYSTAL STRUCTURE OF A NA(I) COMPLEX WITH 4,4’-BIPYRIDINE AND 2-FORMYL- BENZENESULFONATE-HYDRAZINE
TAI XI-SHI(1*), WANG GUANG-LI(2), LIU YUAN-YUAN(1)
A Na(I) complex, [Na(4,4’-bipyridine)2·(H2O)4]·L·OH·2H2O (L = 2-formyl-benzenesulfonate-hydrazine), has been synthesized. And its structure was determined by X-ray single crystal diffraction analysis. The Na(I) complex belongs to orthorhombic, space group C2221 with a = 7.9162(16) Å, b = 18.451(4) Å, c = 26.397(5) Å, V= 3855.7(13) Å3, Z = 4, Dc = 1.394 mg·m-3, μ = 0.218 mm-1, F(000) =1689, and final R1 = 0.0683, ωR2 = 0.2017. The result shows that the Na(I) center is six-coordination with a N2O4 distorted octahedral coordination environment. The Na(I) complex forms 1D chain structure by the π-π stacking interaction.
SYNTHESIS, CRYSTAL STRUCTURE AND LUMINESCENT PROPERTY OF A DINUCLEAR Tb(II) COMPLEX WITH HOMOPHTHALIC ACID AND 2,2’-BIPYRIDYL
LI-HUA WANG(*)
A novel dinuclear Tb(III) complex, [Tb(bpy)2L2] (bpy = 2,2’-bipyridine, H2L = homophthalic acid), has been synthesized and characterized by elemental analysis and single-crystal X-ray diffraction. The Tb(III) complex is monoclinic, space group P21/c with a = 9.368(2) Å, b = 15.948(4) Å, c = 12.216(3) Å, β = 103.023(4)º, V= 1778.2(7) Å3, Z = 2, Dc = 1.910 mg·m-3, μ = 4.011 mm-1, F(000) = 996, and final R1 = 0.0602, ωR2 = 0.2192. The result shows that the Tb(III) center is seven-coordination with a N2O5 distorted pengonal bipyramidal geometry. The luminescent property of Tb(III) complex was investigated.
CETONIZATION, DESARYLATION AND ESTERIFICATION IN THE INTERACTIONS BETWEEN PhPO3H2 AND SnPh3Cl: SYNTHESIS OF OC[OPOSnPh3OEt]2 AND INFRARED STUDY
MODOU SARR, AMINATA DIASSE-SARR, LIBASSE DIOP(*)
On allowing PhPO3H2 to react with SnPh3Cl in ethanolic media, OC[OPOSnPh3OEt]2 is obtained by cetonization, desarylation and esterification, has been studied by infrared technic. A discrete structure has been suggested on the basis of infrared data, the anion behaving as a bidentate ligand, the environment around the tin centres being tertrahedral.