Test results of a Stirling engine utilizing heat exchanger modules with an integral heat pipe

The Heat Pipe Stirling Engine (HP-1000), a free-piston Stirling engine incorporating three heat exchanger modules, each having a sodium filled heat pipe, has been tested at the NASA-Lewis Research Center as part of the Civil Space Technology Initiative (CSTI). The heat exchanger modules were designed to reduce the number of potential flow leak paths in the heat exchanger assembly and incorporate a heat pipe as the link between the heat source and the engine. An existing RE-1000 free-piston Stirling engine was modified to operate using the heat exchanger modules. This paper describes heat exchanger module and engine performance during baseline testing. Condenser temperature profiles, brake power, and efficiency are presented and discussed

HDTV Systems

Case Description: The primary subject matter of HDTV Systems is capital budgeting within a mid-size electronics firm, and analysis of a possible merger with a large firm of international scale. HDTV Systems is recommended for students who have already had exposure to capital budgeting, cost of capital, and valuation techniques; thus, it is most appropriate for upper-level undergraduate students and second year graduate students. The case can be taught in two class hours, and student preparation should require no more than two hours. Case Synopsis: This case involves both quantitative and qualitative aspects of capital budgeting in a firm whose principal owner desires growth and new products but finds constraints primarily due to the size of the company. The case begins with a description of HDTV Systems as a closely-held company with limitations to growth. It presents limitations to funding and shortfalls in analytical processes. Cash flow estimates for a new consumer television product are presented as well as the project\u27s internal rate of return and payback period. The student will learn that capital budgeting is a complex process going beyond calculations of investment worth. As the analysis of the capital expenditure is carried out, HDTV Systems entertains being acquired by Global Electronics. The combination is seen as perhaps offering a more realistic setting for the large capital expenditure for manufacturing the new television project. The case draws out financial motivations for the potential merger, as well as projections of free cash flow for HDTV Systems as a division of Global. © 2009 by the DreamCatchers Group

Excitation Energy Dependence of the Exciton Inner Ring

We report on the excitation energy dependence of the inner ring in the exciton emission pattern. The contrast of the inner ring is found to decrease with lowering excitation energy. Excitation by light tuned to the direct exciton resonance is found to effectively suppress excitation-induced heating of indirect excitons and facilitate the realization of a cold and dense exciton gas. The excitation energy dependence of the inner ring is explained in terms of exciton transport and cooling.Comment: 5 pages, 4 figure

The Effect of Functional Movement Screen-Based Circuit Training On Balance and Postural Stability

Please view abstract in the attached PDF file

Black Holes at the IceCube Neutrino Telescope

If the fundamental Planck scale is about a TeV and the cosmic neutrino flux is at the Waxman-Bahcall level, quantum black holes are created daily in the Antarctic ice-cap. We re-examine the prospects for observing such black holes with the IceCube neutrino-detection experiment. To this end, we first revise the black hole production rate by incorporating the effects of inelasticty, i.e., the energy radiated in gravitational waves by the multipole moments of the incoming shock waves. After that we study in detail the process of Hawking evaporation accounting for the black hole's large momentum in the lab system. We derive the energy spectrum of the Planckian cloud which is swept forward with a large, O (10^6), Lorentz factor. (It is noteworthy that the boosted thermal spectrum is also relevant for the study of near-extremal supersymmetric black holes, which could be copiously produced at the LHC.) In the semiclassical regime, we estimate the average energy of the boosted particles to be less than 20% the energy of the neutrino-progenitor. Armed with such a constraint, we determine the discovery reach of IceCube by tagging on "soft" (relative to what one would expect from charged current standard model processes) muons escaping the electromagnetic shower bubble produced by the black hole's light descendants. The statistically significant 5-sigma excess extends up to a quantum gravity scale ~ 1.3 TeV.Comment: Matching version to be published in Phys. Rev.

Improving empathy of physicians through guided reflective writing

Objectives: This study was designed to explore how guided reflective writing could evoke empathy and reflection in a group of practicing physicians. Methods: Total participants recruited included 40 staff physicians at Cleveland Clinic, a tertiary care academic medical center. Twenty physicians (intervention group) were assigned to participate in a 6-session faculty development program introducing narrative medicine and engaging in guided reflective writing. Ten physicians (comparison group 1) received the assigned course reading materials but did not participate in the course sessions. Ten physicians (comparison group 2) neither received the reading materials nor participated in the sessions. Qualitative analysis of the physicians\u27 reflective writings was performed to identify major themes. The Jefferson Scale of Empathy was administered three times during the course. Results: Qualitative analysis of physicians\u27 writings showed themes of both compassionate solidarity and detached concern. Exploration of negative emotions occurred more frequently than positive ones. The most common writing style was case presentation. A total of 36 staff physicians completed the Jefferson Scale of Empathy. Results of statistical analysis suggested an improvement in empathy in the intervention group at the end of the course (p \u3c 0 .05). Conclusions: These results suggest a faculty development program using guided narrative writing can promote reflection and may enhance empathy among practicing physicians. These findings should encourage medical educators to design additional strategies for enhancing reflection and empathic behavior in trainees and specifically practicing physicians who can role model these behaviors to achieve the ultimate goal of improving the quality of patient care