Browsing by Author "Irosha, K.P.C."

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An Initial Study on Understanding the Effect of Questions Structure on Students' Exam Performance
(3rd International Conference on Advances in Computing and Technology (ICACT ‒ 2018), Faculty of Computing and Technology, University of Kelaniya, Sri Lanka., 2018) Wijesinghe, S.; Irosha, K.P.C.; Rupasinghe, T.
The main challenge in evaluating students’ performance is creating effective assessments which appraises students’ learning rather than their memory power and the practice. According to education theories, creative and carefully designed assessments can clearly evaluate the degree of learning in students. “Scaffolding” which refers to the degree to which a question guides the student through the problem-solving process is a widely used method in aiding students’ learning and conceptual understanding and assessing students’ performance in Science and Technology education. The objective of the current study was to understand the impact of exam question structure on the performance of first year undergraduates specifically focusing on understanding the effect of scaffolded questions. In the current Sri Lankan science education context, there is only a limited number of research studies that are available which provides an insight into the relationship between students’ performance and question features. Current study which was designed to address this issue was conducted as a part of the Chemistry for Technology course at the Faculty of Computing and Technology, University of Kelaniya, Sri Lanka. In this study, two different structures of the same questions were given to students as a part of an in class quiz. First one was a direct question and the second version (scaffolded question) included the same question in a step by step manner and in the latter version, students had to answer several steps to solve the problem. Marks obtained for the two versions were averaged and compared to investigate whether there is any significance of the structure of the questions towards the performance of students. Average mark for the scaffolded question was 82(±20) and the direct question was 71(±35). According to the results, it was clear that the students meet a considerable difficulty in the understanding the direct questions and the scaffolding of questions results in an increase of the performance of students. According to preliminary data, it can be concluded that scaffolding of questions preferentially assist students performance at examinations and surface features such as the structure of the question can play a key role in students’ performance at the examinations. Further studies are currently being conducted to understand whether there is any specific correlation between the improvement in performance as a consequence of scaffolding with the gender, school district and students’ English literacy.
Surface characterization of chemically modified biochar derived from rice straw
(Faculty of Science, University of Kelaniya, Sri Lanka, 2016) Irosha, K.P.C.; de Silva, D.S.M.; Rathnaweera, D.R.
Biochar produced by decomposing variety of biomass feedstock is a carbon rich product that act as an efficient material for various applications such as contaminant management in soil and water, soil amendment in agriculture etc. Biochar obtained from biomass such as wood, manure and leaves have been studied worldwide for their adsorptive capacity, but reports on use of rice straw for such applications are limited. Hence the objective of the present study is to produce biochar using locally available rice straw. Samples of rice straw were chemically decomposed at 400 °C with H3PO4. In order to find a suitable surface modifier to increase the surface porosity and acidity, the resulted biochar materials were treated separately with oxidizing agents such as HNO3, KOH and H2O2. The pore size distribution of modified and the control samples were studied using scanning electron microscopy (SEM) technique. The functional groups available on biochar prior to and after chemical modifications were analyzed using the Fourier transform infrared spectroscopic (FTIR) technique. The FTIR spectral analyses disclosed significant increase in concentrations of the functional groups (carboxylic, alcoholic hydroxyl, phenolic hydroxyl and carbonyl) available on the surface of the KOH treated sample. The SEM analysis revealed about 40% increment in pore diameter of the rice straw biochar that was modified with KOH and H2O2 in contrast to non-modified biochar. Hence, according to the present study, the surface of the decomposed rice straw can be effectively modified with KOH to increase its surface porosity and functionality.