The Effectiveness of Radial Categories in Facilitating EFL learners' Cognitive Operations for Learning Phrasal Verbs

Mastery of English phrasal verbs is regarded as a stumbling block for English language learners, even at advanced levels. Possible sources of difficulty can be a lack of clear meaning and the random nature of particles. The lack of an organized approach to present phrasal verbs to the learners might be a factor that could exacerbate the situation of learning them. This study takes this issue as its point of departure. It investigates whether employing radial categories, conceptual categories with one prototypical concept and some peripheral members that are organized around it, is influential in the learning and long-term retention of these verbs. Moreover, the effect of employing radial categories to teach PVs on learners' cognitive load is investigated. For this purpose, 60 intermediate high school students in 10th and 11th grade were assigned to two groups, one experimental and one control group, each containing 30 students. The study results indicated that the experimental group learners who were taught phrasal verbs using radial categories outperformed control group learners who were taught using a traditional approach. This result suggests that radial categories may help facilitate learning phrasal verbs

Magnetite nanoparticles with surface modification for removal of methyl violet from aqueous solutions

In this research, the potential of Fe3O4 magnetic nanoparticles (MNPs) for efficient removal of methyl violet as a cationic dye from aqueous solutions was investigated. For this purpose, Fe3O4 MNPs were synthesized via chemical precipitation method. The synthesized MNPs were characterized by XRD and SEM techniques. To remove methyl violet, the surface of the MNPs was modified with sodium dodecyl sulfate (SDS) as an anionic surfactant. Also, the various parameters affecting dye removal were investigated and optimized. The kinetic studies for methyl violet adsorption showed rapid sorption dynamics by a second-order kinetic model, suggesting chemisorption mechanism. Dye adsorption equilibrium data were fitted well to the Langmuir isotherm rather than Freundlich isotherm. The maximum monolayer capacity, (qmax), was calculated from the Langmuir as 416.7 mg g−1. The results show that, SDS-coated magnetic nanoparticles, can be used as a cheap and efficient adsorbent for removal of cationic dyes from aqueous solutions