The main goal of the article is to present the current stage of work on the Spontaneity - Reactivity Scale (S-RS). The Scale serves as an assessment of the extent to which children in preschool and younger school age are ready to learn under the guidance of a teacher. The increase in reactivity of the child and the decline of his spontaneity is regarded as an indicator of readiness. In the course of work on Scale it turned out that its positions are grouped around two non-orthogonal factors: the level of socialization of the will and the level of operating in the field of attention. Theoretical and psychometric analysis confirmed both the validity and reliability of the tool. Validity was estimated by confirmation analysis with good model fit to the data (CFI = 0.932; TLI = 0.920; RMSEA = 0.074 [0,069-0,079]; SRMR = 0.054; AGFI = 0.894) and on the basis of relations with contextual variables (positive correlation with age r = 0.47, p <0.001; higher scores of girls: F (1, 917) = 34.51, p <0.001). The reliability with the Cronbach’s coefficient also reached a satisfactory level: full scale alpha = 0.92 [0,91-0,94], for subscales, respectively 0.86 and 0.92. The tool allows to diagnose children at an older age than in the group of 6-year olds, due to the lack of ceiling effect - the average results oldest children which we tested were at a level of 75% of full scale. In opinions of teachers and educators the Scale gained is a simple to use tool with easy to interpret the results. Key words: spontaneity, reactivity, learning under the guidance of a teacher, psychometric properites
In this paper, the ability of nZVI to remove heavy metals (Cd, Cu, Ni, Pb, Zn) from multicomponent aqueous solutions was investigated through batch experiments. The experimental data were fitted to a second-order kinetic model based on solid capacity. The data for copper and lead fitted well into the second-order kinetic model, thus suggesting that the adsorption had a physical character. The values of the removal ratio and the second-order rate constant indicated that the order of adsorption priority of nZVI was as follows: Pb>Cu>Zn>Cd>Ni. The adsorption isotherm data were described by the most conventional models (Henry, Freundlich, and Langmuir). Equilibrium tests showed that copper and zinc were removed from the solution by adsorption processes, i.e., complexation and competitive adsorption. The test results suggested that the removal processes using nZVI are more kinetic than equilibrium. The study demonstrated that nZVI is favorable reactive material; however, comprehensive investigation should be performed for further in situ applications in PRB technology.
In the present work we have calculated several DFT reactivity descriptors for quinclorac at the B3LYP/6- 311++G(2d,2p) and MP2/6-311++G(2d,2p) levels of theory in order to analyze its reactivity. Reactivity descriptors such as ionization energy, molecular hardness, electrophilicity, condensed Fukui function and total energies were determined to predict the reactivity of quinclorac. The influence of the solvent was taken into account employing the PCM model. The results indicate that the solvation modifies the values of quinclorac reactivity descriptors. The Fukui function values predict that an electrophilic attack on quinclorac might cause a dechlorination, while a nucleophilic attack might lead to a decarboxylation and a free radical attack would cause a hydrogen substitution on the quinoline ring. Quinclorac in deprotonated form would be susceptible to decarboxylation through an electrophilic attack while nucleophilic and free radical attacks would cause an attack on the hydrogens of the ring.
The partitioning and transmutation (P&T) of spent nuclear fuel is an important field of present development of nuclear energy technologies. One of the possible ways to carry out the P&T process is to use the accelerator driven systems (ADS). This technology has been developed within the EURATOM Framework Programmes for several years now. Current research in this field is carried out within the scope of 7th FP project FREYA. Important parts of the project are experiments performed in the GUINEVERE facility devoted to characterising the subcritical core kinetics and development of reactivity monitoring techniques. The present paper considers the effects of control rods use on the core reactivity. In order to carry out the evaluation of the experimental results, it is important to have detailed core characteristics at hand and to take into consideration the differences in the effect of control rods acting separately or together (the so-called shadow effect) on both the reactivity value and the measured neutron flux. Also any core asymmetry should be revealed. This goal was achieved by both MCNP simulations and the experimental results. However, in the case of experimental results, the need for calculating respective correction factors was unavoidable.
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.