Volume 10, No. 3 (2009)
Articles
X RAY STRUCTURE OF TETRABUTYLAMMONIUM CHLOROTRIMETHYLTIN HYDROGENOSULPHATE: THE FIRST CYCLIC DIMER HYDROGENOSULPHATO HYDROGEN BONDED ADDUCT
WALY DIALLO(1), AMINATA DIASSÉ-SARR(1), LIBASSE DIOP1(*), BERNARD MAHIEU(2), MONIQUE BIESEMANS(3), RUDOLPH WILLEM(3), GABRIELLE KOCIOK-KÖHN(4), KIERAN C. MOLLOY(4)
The reaction of trimethyltin (IV) chloride with tetrabutylammonium hydrogenosulphate leads to the formation of Bu4NHSO4.SnMe3Cl, the crystal structure of which has been determined by X-ray analysis. The structure consists of a discrete dimer, in which two hydrogen sulphate anions, each coordinated to a trimethyltin chloride moiety (SnMe3Cl) are held together by hydrogen bonds. The tin centre displays a trans OClC3 trigonal bipyramid configuration. Additional infrared, Mössbauer and NMR spectroscopic data are reported.
SYNTHESIS AND CHARACTERIZATION OF TOPO AND HDADMDPA. APPLICATION IN URANIUM (VI) EXTRACTION<br/> SYNTHESE ET CARACTERISATION DU TOPO ET DE L’AHDADMDP. APPLICATION A L’EXTRACTION DE L’URANIUM (VI)
ABDELHAKIM KADOUS(1), LAALDJA MEDDOUR-BOUKHOBZA(2), MOHAMED AMINE DIDI(1*), DIDIER VILLEMIN(3)
The present work concerns the synthesis of two extractive agents: trioctyl phosphine oxide (TOPO) and [(hexadecylamino)di(methylene)]bis(phosphonic acid) (HDADMDPA) and their applications in the extraction of uranium (VI).The influence of extraction time, extractant/metal molar ratio and acid concentration in aqueous phase have been studied. The synthesis of TOPO has reached a yield of 67% and that of HDADMDPA was 73%. The analysis of synthetic products has proved that the desired compounds were synthesized. The extraction yield of uranium (VI) by HDADMDPA in hydrochloric acid was 32% and 56% with TOPO.
MODULAR NEURAL NETWORK MODELING FOR REFRACTIVE INDICES OF SOME BINARY SYSTEMS
GABRIELA LISA(*), CĂTĂLIN LISA, SILVIA CURTEANU
In this work, a modular neural network (MNN) model for prediction of the thermodynamic properties was established. The numbers of patterns used in this study were 175, 160 for training and 15 for validation phases. After evaluating a large number of trials with various MNN architectures, the optimal model was a network with two hidden layers, with 8 neurons in the first and, also, in the second layer, the slabs having the possibility of three activation functions and a jump connection. The mean percentage errors obtained with the best MNN model was of 0.0817%. This result implies that the designed MNN model was properly capable of learning the relationship between the input and output parameters and also confirms that the neural network was able to reproduce simultaneously more that one system, unlike traditional models where one mathematical model was required for each system.
THERMAL BEHAVIOR OF SOME NEW PHENOXYALKYL CARBOXYLIC ACIDS DERIVATIVES IN NITROGEN ATMOSPHERE
ANCA MIHAELA MOCANU(1*), LUCIA ODOCHIAN(2)
In the present paper new compounds are characterized by TG-DTG-DTA thermal methods in order to investigate the structure-thermostability-degradation mechanism correlation. The results of thermal analysis are indicative of a complex degradation mechanism which is characteristic of every sample, some similarities reflecting the structure influence being also noticed. The initial degradation temperatures resulting from TG-DTG-DTA led to the estimation of the temperature range of using and storing these compounds which is an useful information if their possible practical applications and of some derivatives as herbicides, plant growth stimulators, fungicides, acaricides are taken into account. Apart from this, the presence of the diazo and azo group in the structure of these new compounds could make possible some useful applications for dying of proteic fibres.
CHARACTERIZATION AND LIGNIN DEGRADATION PROPERTIES OF THE LIGNINOLYTIC ENZYMES IN THE EXTRACELLULAR FLUIDS OF PHANEROCHAETE CHRYSOSPORIUM 1038
NELLY V. GEORGIEVA(1*), LYUBOV K. YOTOVA(1), TINKA G. KOLUSHEVA(2), NADEZHDA G. RANGELOVA(3)
The effect of ligninolytic enzymes in the extracellular fluids of the cultivated cells of basidiomycetic fungi of Phanerochaete chrysosporium strain 1038 on hydrolyzed lignin samples in vitro was investigated. The growth conditions of the strain were optimized in regard to receive higher activities of ligninolytic enzymes. The influence of inorganic nitrogen, Mn2+ ions, temperature and pH of the medium on the growth and enzymes activity was also studied. It was found that extracellular fluids of the cultivated strain showed activities of lignin peroxidase (LiP), manganese peroxidase (MnP) and laccase (Lac). The addition of 2.2 mM nitrogen and 3.5 mg/L Mn2+ to the medium kept constantly at 37° ;C and pH = 5 increased significantly the quantity of exuded by cells soluble protein with considerable activities of LiP, MnP and Lac. The extracellular fluids, concentrated by ultrafiltration were incubated for 24 h with samples of hydrolysis lignin. Evidence for the delignification processes was provided by FTIR spectroscopy, which showed decrease of free carboxylic and increase of hydroxylated and methoxylated aliphatic groups in the treated samples. The changes were regarded as result of oxygenation processes caused by the extracellular ligninolytic enzymes.
THE EFFECT OF HYDRIC STRESS UPON THE SYNTHESIS OF FOUR ISOENZYMES OF TWO VARIETIES OF DURUM WHEAT<br/> EFFET DU STRESS HYDRIQUE SUR LA SYNTHESE DE QUATRE ISOENZYMES DE DEUX VARIETES DE BLE DUR
W. ZERRAD(1), B.S. MAATAOUI(2), S. HILALI(2), S. EL ANTRI(1), S. LAZAR(1*), A. HMYENE(1)
The effect of water stress on 4 enzymatic systems: peroxidases, malate dehydrogenases, esterases and phosphatases of coleoptiles and roots of two varieties of durum wheat Karim and Tomouh was evaluated by electrophoretic analysis. Water conditions have stimulated the synthesis of peroxidases in the coleoptiles and malate dehydrogenases in the roots of both varieties studied. Drought has also induced the synthesis of peroxidases, esterases and phosphatases at the roots of variety Karim.
THE MATHEMATICAL MODEL OF EDIBLE OILS PHYSICAL REFINING
IULIANA VINTILA
A differential vaporization model is proposed in the present research paper in order to simulate the batch physical refining and/or deodorization process used in the vegetable oil industry. The fractionate distillation based on the differential vapor–liquid equilibrium of oil systems and the steam entrainment of distillate compounds process are mathematically designed in a differential equation for the vapor pressures and activity coefficients.
RELATIONSHIPS BETWEEN THE RYE QUALITY FACTORS
IULIANA BANU(*), INA VASILEAN
The processing value of the grain can be predicted by combining measurements made from grain, flour, or dough and combining them into prediction models. This study evaluated the correlations between grain rye quality factors: proximate structural and compositional particularities, endosperm matrix protein, and milling performance. Those three factors, derived from the orthogonal transformation of the matrix, were retained to explain 91.8% of the variation according to eigenvalues. Twelve samples of rye have been analysed: four rye varieties (Orizont, Suceveana, Gloria and Impuls) from the crop years 2004, 2005, 2006.
EFFECT OF SOME TECHNOLOGICAL FACTORS ON THE CONTENT OF ESTERS IN BEER
GUNKA N. JONKOVA, NELLY V. GEORGIEVA(*)
The purpose of this work was to examine the influence of the fermentation conditions such as temperature, the pitching rate of yeast and the “Free Amino Nitrogen” (FAN) in wort on the content of esters in beer. It has been found out that the higher temperature of fermentation stimulates the formation of esters and quantity in the beer is higher. Beer, obtained by increased pitching rate (26.106 and 35.106 cells/mL), contains the same or less amount of esters compared to that in the control beer. Lower content of FAN in wort must result in the replacement of 5 to 10% of the malt with rice, sugar or a combination thereof, leads to a high content of esters in beer.
VALORIZATION OF STEEL INDUSTRY WASTEWATERS IN THE DECOLORIZATION OF DYES CONTAINING SOLUTIONS
ABDELKADER ANOUZLA(*), SALAH SOUABI, MOHAMED SAFI, ABDAZIZ ABOULHASSAN, HICHAM RHBAL, YOUNES ABROUKI
The aim of the present work is to test the ability of the steel industry wastewater (SIWW) iron rich as an original coagulant to remove the textile dyes from wastewaters of textile industry. The SIWW was used in the treatment of four textile dye solutions, namely orange HER, red F2B, blue SRN, and as well as their mixture. Jar-test experiments were employed in order to determine the optimum conditions for the removal of organic and colored matters. The results showed that: SIWW is effective in the removal of COD and color, it is efficient at a wide pH range, and produced a less volume of decanted sludge compared to classical coagulant FeCl3.
FIGHTING AGAINST NITRATE POLLUTION OF THE DAM-RETAINED WATERS THROUGH BIOLOGICAL TREATMENT
WASSILA CHEURFI, HASSINA BOUGHERARA(*), OUISSAF BENTABET, KHALED BATOUCHE, BRAHIM KEBABI
Pollution of the water by nitrates was favored by setting husbandry intensive methods of production, which was implemented by an increased use of chemical manures. Most of this pollution is due to the difference in the proportion of nitrates in manures and what is actually uptaken by the plants. In response to this issue, we carried out a research intended for reducing the concentration of nitrates in the water streams supplying the Dam of Beni Haroun, Algeria, in order to avoid the eutrophication fatal effects. This was achieved thanks to a biological treatment, which is one of the cheapest and most efficient for reducing nitrates. In our paper, we used a mixed culture of microorganisms picked up in the El Menia Filtering Station, Constantine, Algeria. The use of methanol as a carbon source involved a rise in pH. In order to prevent the consequences on the degradation performance of the microorganisms, a buffer mixture of acetic acid and sodium acetate was used as a source of carbon. We noticed a growth in bacteria coupled with elimination proportionate to nitrates. During this elimination, the medium pH varies slightly, it moves from 7.00 to 7.88. This has improved denitrification, reducing the treatment time and increasing the denitrification rate. On the other hand, this work allowed to state that the best denitrification rate was obtained for the ratio value C/N that equals 2.5.