Dandelion Diagram: Aggregating Positioning and Orientation Data in the Visualization of Classroom Proxemics

In the past two years, an emerging body of HCI work has been focused on classroom proxemics - how teachers divide time and attention over students in the different regions of the classroom. Tracking and visualizing this implicit yet relevant dimension of teaching can benefit both research and teacher professionalization. Prior work has proved the value of depicting teachers' whereabouts. Yet a major opportunity remains in the design of new, synthesized visualizations that help researchers and practitioners to gain more insights in the vast tracking data. We present Dandelion Diagram, a synthesized heatmap technique that combines both teachers' positioning and orientation (heading) data, and affords richer representations in addition to whereabouts - For example, teachers' attention pattern (which directions they were attending to), and their mobility pattern (i.e., trajectories in the classroom). Utilizing various classroom data from a field study, this paper illustrates the design and utility of Dandelion Diagram.Comment: To be published in CHI'20 Extended Abstracts (April 25-30, 2020), 8 pages, 4 figure

Flux-cutting and flux-transport effects in type-II superconductor slabs in a parallel rotating magnetic field

The magnetic response of irreversible type-II superconductor slabs subjected to in-plane rotating magnetic field is investigated by applying the circular, elliptic, extended-elliptic, and rectangular flux-line-cutting critical-state models. Specifically, the models have been applied to explain experiments on a PbBi rotating disk in a fixed magnetic field ${\bm H}_a$, parallel to the flat surfaces. Here, we have exploited the equivalency of the experimental situation with that of a fixed disk under the action of a parallel magnetic field, rotating in the opposite sense. The effect of both the magnitude $H_a$ of the applied magnetic field and its angle of rotation $\alpha_s$ upon the magnetization of the superconductor sample is analyzed. When $H_a$ is smaller than the penetration field $H_P$, the magnetization components, parallel and perpendicular to ${\bm H_a}$, oscillate with increasing the rotation angle. On the other hand, if the magnitude of the applied field, $H_a$, is larger than $H_P$, both magnetization components become constant functions of $\alpha_s$ at large rotation angles. The evolution of the magnetic induction profiles inside the superconductor is also studied.Comment: 12 pages, 29 figure

Development and test of advanced composite components. Center Directors discretionary fund program

This report describes the design, analysis, fabrication, and test of a complex bathtub fitting. Graphite fibers in an epoxy matrix were utilized in manufacturing of 11 components representing four different design and layup concepts. Design allowables were developed for use in the final stress analysis. Strain gage measurements were taken throughout the static load test and correlation of test and analysis data were performed, yielding good understanding of the material behavior and instrumentation requirements for future applications

Chemochromic Indicators for the Detection of Hypergolic Fuels

The toxicity and hazard level associated with the use of hypergolic fuels necessitates the development of technology capable of detecting the presence of such fuels in a variety of different environments and conditions. The most commonly used sensors for the detection of hypergolic fuels are electrochemical in nature, which have serious limitations when used as area monitoring devices. Recent collaborative work between Kennedy Space Center and ASRC Aerospace has led to the development of indicators which exhibit a color change upon exposure to hydrazine under different conditions. The indicators under investigation on this developmental effort are para-dimethylaminobenzaldehyde (PDAB), various formulations of universal pH indicators, and potassium tetrachloroaurate (KAuCl4). These chemochromic indicators have been tested for the detection of hydrazine under various conditions: pure liquid fuel, aqueous fuel solution, saline aqueous fuel solutions, vapor fuel, and 3-month shelf life study, which included UV protection, thermal extremes, and normal storage conditions. The hypergolic fuel indicator test was conducted with the indicator impregnated into a wipe material to test the applicability of the indicator to be used to capture (absorb) and indicate the presence of hypergolic fuels. Each of the indicators performed well, with the universal pH indicator being the best candidate because of the visible response color change and the indicator stability after the shelf life study

Designing OLMs for reflection about group brainstorming at interactive tabletops

Brainstorming is a valuable and widely-used group technique to enhance creativity. Interactive tabletops have the potential to support brainstorming and, by exploiting learners' trace data, they can provide Open Learner Models (OLMs) to support reflection on a brainstorming session. We describe our design of such OLMs to enable an individual to answer core questions: C1) how much did I contribute? C2) at what times was the group or an individual stuck? and C3) where did group members seem to 'spark' off each other? We conducted 24 brainstorming sessions and analysed them to create core brainstorming models underlying the OLMs. We evaluated the OLMs in a think-aloud study designed to see whether learners could interpret the OLMs to answer the core questions. Results indicate the OLMs were effective and that it is valuable, that learners benefit from guidance in their reflection and from drawing on an example of an excellent group's OLM. Our contributions are: i) the first OLMs supporting reflection on brainstorming; ii) models of brainstorming that underlie the OLMs; and iii) a user study demonstrating that learners can use the OLMs to answer the core reflection questions

Incorporation of alpha-Ketoglutaric Acid as a Fixed Bed Scrubber Media for the Neutralization of Hydrazine Family Hypergolic Fuels

A candidate scrubber media, alpha-ketoglutaric acid (aKGA) adsorbed onto a silica-based substrate was examined as a potential alternative to the hydrazine-family hypergolic fuel neutralization techniques currently utilized at NASA/Kennedy Space Center (KSC). Helvenson et. al. has indicated that aKGA will react with hydrazines to produce non-hazardous, possibly biodegradable products. Furthermore, the authors have previously tested and demonstrated the use of aKGA aqueous solutions as a replacement neutralizing agent for citric acid, which is currently used as a scrubbing agent in liquid scrubbers at KSC. Specific properties examined include reaction efficiency, the loading capacity of aKGA onto various silica substrates, and the comparison of aKGA media performance to that of the citric acid vapor scrubber systems at KSC and a commercial vapor scrubber media. Preliminary investigations showed hydrophobic aerogel particles to be an ideal substrate for the deposition of the aKGA. Current studies have shown that the laboratory produced aKGA-Aerogel absorbent media are more efficient and cost effective than a commercially available fixed bed scrubber media, although much less cost effective than liquid-based citric acid scrubbers (although possibly safer and less labor intensive). A comparison of all three alternative scrubber technologies (liquid aKGA, solid-phase aKGA, and commercially available sorbent materials) is given considering both hypergolic neutralization capabilities and relative costs (as compared to the current citric acid scrubbing technology in use at NASA/KSC)