119 research outputs found
Multiple scattering of MeV ions: Comparison between the analytical theory and Monte-Carlo and molecular dynamics simulations
Scenario Evaluation with Relevance and Interest (SERI): Development and Validation of a Scenario Measurement Tool for Context-Based Learning
Context-based learning (CBL) approaches have been recommended and expanded in science education to make science more relevant to students by connecting science content with students’ daily life. Subsequently, in order to implement CBL at school, a group of scenarios has been produced by several stakeholders. However, there is a lack of resources to measure effectively what makes a good scenario. Thus, this study aims to develop and validate a scenario evaluation instrument to examine students’ perspectives on science career-related scenarios through the lens of relevance and interest. For this purpose, 25 science career-related scenarios and a measurement tool, Scenario Evaluation with Relevance and Interest (SERI), were developed by a team of researchers for the EU funded MultiCO project. Then, lower secondary school students from three different countries, Estonia, Finland, and the UK, were asked to respond to the newly developed instrument after reading the scenarios, and their responses were analyzed by factor analyses and multivariate analysis of variance. According to the result, this instrument has good construct validity and reliability. However, it indicates one issue of discriminant validity between two factors, individual dimension and societal dimension. Also, significant gender differences were found in the Estonian sample regarding students’ perspectives on the scenarios. Possible interpretations of the results and implications of the suggested measurement tool are discussed
First-principles simulation of intrinsic collision cascades in KCl and NaCl to test interatomic potentials at energies between 5 and 350 eV
Theoretical interatomic potentials for KCl and NaCl are tested at energies 5–350 eV against experimental data from intrinsic collision cascades. The collisional scattering of Cl with Cl, K, and Na atoms was observed from Doppler-shifted γ rays depopulating an excited state in recoiling Cl36 produced through the thermal neutron capture Cl35(n,γ)36Cl. The collisional scattering was simulated with molecular dynamics. Interatomic potentials from the present Iab initioP atomic cluster calculations are proposed for the Cl-Cl, Cl-K, and Cl-Na interactions in KCl and NaCl.Peer reviewe
A Revised Pedagogy Model for Simulator-Based Training with Biomedical Laboratory Science Students
Methods based on simulation pedagogy are widely used to practice hands-on skills in safety environment. The usability of an EEG simulator on clinical neurophysiology course was evaluated. Second-year biomedical laboratory science students (N = 35) on this course were included in the study. They were divided into three groups. Two groups used the EEG simulator with different feedback modes and one group did not use the simulator. Results were expected to reveal a correlation between user experience and learning outcomes. This study made used of a mixed method study design. During the study, students were asked to keep a learning diary throughout the course on their experience. Diaries were analyzed qualitatively based on content analyses. Quantitative analyses based on an UX questionnaire that measures classical usability aspects (efficiency, perspicuity, dependability) and user experience aspects (novelty, stimulation) and the students' feelings to use simulator. The quantitative data was analyzed using SPSSTM software. The quantitative and qualitative analyses showed that the use of the EEG simulator, which was evaluating teaching-learning process, has an extra benefit in clinical neurophysiology education and students felt that the simulator was useful in learning. The simulation debriefing session should be followed by a full theoretical and practical session. Students compared their learning from the simulator with that of the actual placement which fosters the reflective practice of learning, again deepening the understanding of the EEG electrode placement and different wave patterns
Transition rates and nuclear structure changes in mirror nuclei 47Cr and 47V
Lifetime measurements in the mirror nuclei 47Cr and 47V were performed by
means of the Doppler-shift attenuation method using the multidetector array
EUROBALL, in conjunction with the ancillary detectors ISIS and the Neutron
Wall. The determined transition strengths in the yrast cascades are well
described by full pf shell model calculations.Comment: Latex2e, 11 pages, 3 figure
Cutting and controlled modification of graphene with ion beams
Using atomistic computer simulations, we study how ion irradiation can be
used to alter the morphology of a graphene monolayer by introducing defects of
specific type, and to cut graphene sheets. Based on the results of our
analytical potential molecular dynamics simulations, a kinetic Monte Carlo code
is developed for modelling morphological changes in a graphene monolayer under
irradiation at macroscopic time scales. Impacts of He, Ne, Ar, Kr, Xe and Ga
ions with kinetic energies ranging from tens of eV to 10 MeV and angles of
incidence between 0\circ and 88\circ are studied. Our results provide
microscopic insights into the response of graphene to ion irradiation and can
directly be used for the optimization of graphene cutting and patterning with
focused ion beams
Creating Sources of Inspiration through eCollage, the FEA Model, and a Future Visioning Concept Design Project
This article presents an approach to creating sources of inspiration through a collabora-tive concept design that was developed and observed during a future visioning concept design project concerning the theme of “performance wear,” which was conducted at the University of Helsinki for second-year textile student teachers. During the project, the stu-dents created future scenarios; used the functional, expressive, and aesthetic (FEA) con-sumer needs model for apparel design (Lamb and Kallal in Cloth Text Res J 10(2):42–47, 1992) when considering what performance wear could be like in a future scenario; and cre-ated digital collages (eCollages) to present their concepts. In the course that followed the concept design project, the students designed and made actual clothes using the concepts developed during the concept design project as one of their sources of inspiration. The outcomes of the process are described in this article through four research questions: (1) What type of future scenarios did the teams create, what types of eCollages did the teams make, and how did the teams use information and communication technologies (ICT) in their collages? (2) How did the use of eCollages enrich the concept presentations? (3) How were the three dimensions of the FEA model utilized and presented in the eCollages and team presentations? (4) How did the future visions of the concepts and the eCollages act as sources of inspiration in the students’ clothing designs? Five of the six teams studied created a global future scenario that envisioned the world as a dystopia. The high level of technical and visual executions of all the eCollages was surprising. The ECollages played an important role in every team presentation and enriched them considerably. The FEA model, on the other hand, both provided a supporting framework for the concepts and guided the students to direct their attention to apparel within their future scenarios, as well as to consider different dimensions of it. The concepts especially inspired students to create aesthetic elements to their design and to consider the expressiveness and functionality of the garments from the concept’s perspective. The students also challenged themselves to find technical solutions to design ideas they created through being inspired by the concepts. Furthermore, the students often described gaining inspiration from the story or atmosphere of the concept or other non-visual elements of it, and thereby it seems that our approach indeed succeeded in promoting multi-sensory inspiration.Peer reviewe
Ni+-irradiated InGaAs/GaAs quantum wells: picosecond carrier dynamics
Room-temperature carrier dynamics as functions of heavy-ion implantation and subsequent thermal annealing were investigated for technologically important InGaAs/GaAs quantum wells (QWs) by means of a time-resolved up-conversion method. Sub-picosecond lifetimes were achieved at 10 MeV Ni+ doses of (20-50) x 1010 ions cm-2. The decay rates reached a maximum at the highest irradiation dose, yielding the shortest lifetime of the confined QW states of 600 fs. A simple theoretical model is proposed for the photodynamics of the carriers. The relaxation rate depended on the irradiation dose according to a power law of 1.2, while the irradiated and subsequently annealed samples exhibited a power law of 0.35. The results are qualitatively interpreted.Room-temperature carrier dynamics as functions of heavy-ion implantation and subsequent thermal annealing were investigated for technologically important InGaAs/GaAs quantum wells (QWs) by means of a time-resolved up-conversion method. Sub-picosecond lifetimes were achieved at 10 MeV Ni+ doses of (20-50) x 1010 ions cm-2. The decay rates reached a maximum at the highest irradiation dose, yielding the shortest lifetime of the confined QW states of 600 fs. A simple theoretical model is proposed for the photodynamics of the carriers. The relaxation rate depended on the irradiation dose according to a power law of 1.2, while the irradiated and subsequently annealed samples exhibited a power law of 0.35. The results are qualitatively interpreted.Room-temperature carrier dynamics as functions of heavy-ion implantation and subsequent thermal annealing were investigated for technologically important InGaAs/GaAs quantum wells (QWs) by means of a time-resolved up-conversion method. Sub-picosecond lifetimes were achieved at 10 MeV Ni+ doses of (20-50) x 1010 ions cm-2. The decay rates reached a maximum at the highest irradiation dose, yielding the shortest lifetime of the confined QW states of 600 fs. A simple theoretical model is proposed for the photodynamics of the carriers. The relaxation rate depended on the irradiation dose according to a power law of 1.2, while the irradiated and subsequently annealed samples exhibited a power law of 0.35. The results are qualitatively interpreted.Peer reviewe
First inverse kinematics measurement of key resonances in the 22Ne(p, Îł)23Na reaction at stellar temperatures
In this Letter we report on the first inverse kinematics measurement of key resonances in the reaction which forms part of the NeNa cycle, and is relevant for Na synthesis in asymptotic giant branch (AGB) stars. An anti-correlation in O and Na abundances is seen across all well-studied globular clusters (GC), however, reaction-rate uncertainties limit the precision as to which stellar evolution models can reproduce the observed isotopic abundance patterns. Given the importance of GC observations in testing stellar evolution models and their dependence on NeNa reaction rates, it is critical that the nuclear physics uncertainties on the origin of Na be addressed. We present results of direct strengths measurements of four key resonances in at E = 149 keV, 181 keV, 248 keV and 458 keV. The strength of the important E = 458 keV reference resonance has been determined independently of other resonance strengths for the first time with an associated strength of = 0.439(22) eV and with higher precision than previously reported. Our result deviates from the two most recently published results obtained from normal kinematics measurements performed by the LENA and LUNA collaborations but is in agreement with earlier measurements. The impact of our rate on the Na-pocket formation in AGB stars and its relation to the O-Na anti-correlation was assessed via network calculations. Further, the effect on isotopic abundances in CO and ONe novae ejecta with respect to pre-solar grains was investigated
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