Experiences and Thoughts on STEMTEC-Inspired Changes in Teaching Physics for Life Science Majors

I have taught an introductory course for life science majors three times, each time introducing one or more teaching techniques discussed during the Science, Technology, Engineering, and Mathematics Teaching Education Collaborative (STEMTEC) meetings. Typical class size was 275 students. I cannot make quantitative statements about comparisons between the results of STEMTEC-type teaching methods and traditional teaching methods because I have never taught this course in a completely traditional lecture style. During the first year, I introduced conceptual questions into my lectures. The lecture would be interrupted several times with questions posed to the class. The students then had several minutes to discuss each question among their neighbors, then present their answers. During the second year, I switched from traditional homework to a computerized system which allowed instant feedback to the students, and the ability to resubmit solutions to problems they had not successfully solved. I also introduced an exam format that enabled the students to work individually, then redo the exam in groups and hand in a second set of solutions. The goal of each of these techniques was to increase the engagement of the students with the material of the course. Each of the techniques had both successes and limitations. The most serious problems I confronted were technical difficulties which diverted attention from the tasks at hand to the necessity of keeping the system functioning

High Pressure Effects on Superconductivity in the beta-pyrochlore Oxides AOs2O6 (A=K, Rb, Cs)

Recently new pyrochlore oxides superconductors AOs2O6 (A=K,Rb,Cs) were found and we measured the pressure dependence of magnetization up to 1.2 GPa in order to deduce the pressure effect of Tc in the three beta-pyrochlore oxides. It is found that the initial pressure dependence of Tc is positive for all the compounds. Only KOs2O6 exhibits a saturation in Tc at 0.56 GPa and the downturn at higher pressureComment: 7 pages, 2 figure

Magnetohydrodynamic normal mode analysis of plasma with equilibrium pressure anisotropy

In this work, we generalise linear magnetohydrodynamic (MHD) stability theory to include equilibrium pressure anisotropy in the fluid part of the analysis. A novel 'single-adiabatic' (SA) fluid closure is presented which is complementary to the usual 'double-adiabatic' (CGL) model and has the advantage of naturally reproducing exactly the MHD spectrum in the isotropic limit. As with MHD and CGL, the SA model neglects the anisotropic perturbed pressure and thus loses non-local fast-particle stabilisation present in the kinetic approach. Another interesting aspect of this new approach is that the stabilising terms appear naturally as separate viscous corrections leaving the isotropic SA closure unchanged. After verifying the self-consistency of the SA model, we re-derive the projected linear MHD set of equations required for stability analysis of tokamaks in the MISHKA code. The cylindrical wave equation is derived analytically as done previously in the spectral theory of MHD and clear predictions are made for the modification to fast-magnetosonic and slow ion sound speeds due to equilibrium anisotropy.Comment: 19 pages. This is an author-created, un-copyedited version of an article submitted for publication in Plasma Physics and Controlled Fusion. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from i

Attractive forces in microporous carbon electrodes for capacitive deionization

The recently developed modified Donnan (mD) model provides a simple and useful description of the electrical double layer in microporous carbon electrodes, suitable for incorporation in porous electrode theory. By postulating an attractive excess chemical potential for each ion in the micropores that is inversely proportional to the total ion concentration, we show that experimental data for capacitive deionization (CDI) can be accurately predicted over a wide range of applied voltages and salt concentrations. Since the ion spacing and Bjerrum length are each comparable to the micropore size (few nm), we postulate that the attraction results from fluctuating bare Coulomb interactions between individual ions and the metallic pore surfaces (image forces) that are not captured by meanfield theories, such as the Poisson-Boltzmann-Stern model or its mathematical limit for overlapping double layers, the Donnan model. Using reasonable estimates of the micropore permittivity and mean size (and no other fitting parameters), we propose a simple theory that predicts the attractive chemical potential inferred from experiments. As additional evidence for attractive forces, we present data for salt adsorption in uncharged microporous carbons, also predicted by the theory.Comment: 19 page

Investigating the success factors of expert users to inform device development

Objective: Expert user testing is a well recognised tool within user experience and human computer interaction design. Within the domain of assistive technology device design, however, this technique seems to be little used. It is suggested that studying the success factors of expert assistive technology device users may provide a valuable source of data to inform development of assistive technology devices. This paper presents an example of this technique, within the context of a number of studies carried out by the authors, using the example of preliminary data from a study informing the development of an innovative Augmentative and Alternative Communication (AAC) device. Main Content: The paper presents a qualitative study whose objective was to influence the design and further development of an innovative voice-input voice-output communication aid (Vivoca) which has previously reached proof-of-concept stage. The Vivoca device is designed for people with dysarthria and this dictates a number of specific constraints and considerations. In order to understand how Vivoca could be designed to be used successfully by people with dysarthria, this study aimed to identify the factors associated with expert users' successful use of current AAC devices. In order to allow comparison, the study included users with some understandable speech and also those with no understandable speech. The study procedure was designed to provide a profile of participants' communication methods and to identify the factors that participants felt made their communication successful. Results: Preliminary results from the study (currently underway) are presented, including a qualitative analysis of interview data, and data profiling participants' communication methods and context. Initial data has highlighted the very specific requirements for a communication aid design for people with some understandable speech. Conclusion: Study of expert users may provide an effective tool to help inform assistive technology device development