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Abstract  

In this paper a technique to separate and measure both isotopes (237Np and 239Np) together is presented. A combined shape pulse discrimination liquid scintillation measurement with gamma-spectrometry, permits a precise measurement after the radiochemical separation. This technique was carried out by using an Eichrom chromatographic column (TEVA) as the first step of a more complete method, applied in the Nuclear Regulatory Authority, to separate actinides in nuclear waste and liquid effluents. The MCA is 0.08 Bq/l by alpha-spectrometry and 0.22 Bq/l (2σ) by liquid scintillation counting (LSC) for 93.7% of measurement efficiency and 98.4% of chemical recovery.

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The kinetics of the oxidation-reduction reaction between N,N-diethylhydroxylamine (DEHAN) and vanadium(V) in nitric acid media have been studied by spectrophotometry at 13.5 °C. The rate equation of reaction was found to be -d[V(V)]/dt = k [V(V)] [DEHAN] by investigating the influence of the concentration, acidity, ionic strength and the effect of initial concentration on reaction. The rate constant of reaction k = 36.38 mol/l-2 ·min-1 when = 2.0 mol/l. A possible mechanism of reaction has been suggested on the basis of chemical analysis, 1 H NMR and ESR spectra.

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Extraction of microamounts of strontium and barium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H+B) in the presence of polyethylene glycol PEG 600 (L) has been investigated. The equilibrium data have been explained assuming that the complexes HL+, H2L2+, ML2+ and MHL3+ (M2+ = Sr2+, Ba2+) are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined. It was found that in water-saturated nitrobenzene the stability constant of the BaL2+ cationic complex species is essentially higher than that of the complex SrL2+.

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The compounds ML2(NCS)2, (M(II)=Mn, Co), FeL2(NCS)22H2O, NiL3 NCS)23H2O (L=2,2'-bipyridine, 2-bipy) MX2(NCS)22H2O (M(II)=Mn, Fe; X=4,4'-bipyridine, 4-bipy) have been prepared and their IR spectra and molar conductivity studied. The thermal decomposition of the complexes was studied under non-isothermal conditions in air. During heating the hydrated complexes lose crystallization water molecules in one or two steps and then decompose via different intermediate compounds to the oxides Mn3O4, Fe2O3, CoO, NiO.

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Abstract  

The thermodynamics of the reaction of 1,3,7,13,17,19-hexamethyl-2,8,12,18-tetrabutylbiladiene-a,c (H2L) with cobalt(II) and zinc(II) acetates in dimethylformamide (298.15 K) was studied by spectrophotometric and calorimetric titration. It was found that H2L and Zn(II) form a mononuclear complex ZnL, and in the case of Co(II), a binuclear biligand complex Co2L2 is formed. Thermodynamic characteristics of the formation of Co(II) and Zn(II) complexes with biladiene-a,c in DMF at 298.15 K were determined.

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The study reported in the paper investigates the structure of L2 self-corrections in the speech of 30 Hungarian learners of English and 10 Hungarian native speakers. The aim of the research is to examine what the well-formedness of the corrections, the use of editing terms, the placement of cut-off points and the effect of the participants' level of proficiency on the structure of self-repairs reveal about the psycholinguistic processes of speech production. The results of the study lend additional support for modular models of speech production (e.g., Levelt 1983, 1989; Levelt et al. 1999) and reveal an important role of pragmatic constraints in psycholinguistic processing.

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The use of mature embryos as explants to initiate cultures is a best alternative to save time and costs, especially for producing somatic embryos for genetic transformation of durum wheat. However, plantlets regeneration from cultures derived from matured embryos is usually low. In this study, we tested matured embryos as explants from eight Moroccan durum wheat varieties (‘Irden’, ‘Marzak’, ‘Kyperounda’, ‘Isly’, ‘Amria’, ‘Karim’, ‘Marouane’ and ‘Tomouh’) to define suitable culture media for obtaining high frequencies of somatic embryogenesis and in vitro plantlets regeneration. For this purpose, we tested five induction and maintenance media (M1 to M5) based on MS media (macro and oligo-elements) which differed with respect to concentrations of plant hormones (2,4-D and BA), vitamins, sucrose, maltose, L-asparagine, and solidifying agents. All tested media induced embryogenic callus for the varieties and regenerate plantlets. However, a significant effect of variety, medium and variety × medium interaction were observed for callus induction and regeneration. Average callus growth as measured by relative fresh weight growth rate (RFWGR) across different media was the highest for ‘Amria’ (7215.4%) and the lowest for ‘Tomouh’ (2088.2%). M1 (2 mg/L 2,4-D) and M5 (3 mg/L 2,4-D) media gave highest RFWGR(6892.1% and 6332%, respectively) and M3 (1 mg/L 2,4-D) was the lowest (3708.8%), across different varieties. However, the embryogenic callus from M3 media regenerated the highest percentage of plantlet, upon transfer to regeneration medium, for most of the varieties. For the varieties ‘Marouane’, ‘Kyperounda’, ‘Marzak’, ‘Karim’, and ‘Tomouh’, the favourable medium was M3, whereas, for ‘Isly’, ‘Irden’ and ‘Amria’, both M2 (2.5 mg/L BA and 2.5 mg/L 2,4-D) and M3 were the favourable media for embryogenic callus induction. In this study, for the first time, favourable media for induction and regeneration from mature embryo of Moroccan durum wheat varieties were identified. These media will be used for callus induction and genetic transformation.

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Nine bitter vetch selection lines were evaluated in three successive years to determine their yield and seed index (100-seed weight) stabilities, based on three parameters: phenotypic index (P), regression coefficient (bi), and least deviation from regression (S2 di). The line Sel. 2517 (L7) was identified as the most stable one for the growing seasons, while Sel. 2509 (L2) and Sel. 2511 (L4) were found to be stable for seed yield under favourable climatic conditions. For seed index Sel. 2515 (L6) was identified as the most stable line. Selection line 2513 (L5), which originated from Cyprus, had the highest degree of responsiveness to changing environments.

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Abstract  

The precipitation of uranyl ion with 2-hydroxy-1-naphthaldehyde /2H–1N=HL/ was studied. The solid complex /orange crystals/ was characterized by IR, UV-Vis spectra. Uranium was determined as U3O8 after calcination of the complex at 850°C /37.78% U experimental, 36.64% U calculated for C22H14O6U, UO2L2/. Using a statistical experimental design, the best conditions for quantitative precipitation were obtained. A gravimetric method for the determination of UO 2 2+ is proposed by weighing the complex after drying at 110°C.

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Abstract

By employing new ideas and techniques, we will refigure out the whole frame of L 1-approximation. First, except generalizing the coefficients from monotonicity to a wider condition, Logarithm Rest Bounded Variation condition, we will also drop the prior requirement fL 2π but directly consider the sine or cosine series. Secondly, to achieve nontrivial generalizations in complex spaces, we use a one-sided condition with some kind of balance conditions. In addition, a conjecture raised in [9] is disproved in Section 3.

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