Study of pressure losses in tubing and fittings Quarterly progress report, Dec. 1965 - Feb. 1966

Pressure losses in tubing and fittings - flow systems analysis, entrance effects in flexible metal hoses, and methods for analyzing flow over rough surfac

Vibration effects on heat transfer in cryogenic systems Quarterly progress report, Jul. 1 - Sep. 30, 1967

Water test apparatus used to determine vibration effects on heat transfer in cryogenic system

Vibration effects on heat transfer in cryogenic systems Quarterly progress report no. 1, Jun. 1 - Aug. 31, 1966

Vibration effects on natural convection and fluid transport properties in cryogenic system

Modeling Non-Force-Free and Deformed Flux Ropes in Titan’s Ionosphere

Previous work at Titan presented a set of 85 flux ropes detected during Cassini flybys of Titan from 2005 to 2017. In that study a force‐free model was used to determine the radii and axial magnetic field of the flux ropes. In this work we apply non‐force‐free models. The non‐force‐free model shows an improvement in the number of flux ropes that can be fitted with a model, along with improved uncertainties and χ2 values. A number of asymmetries and features in the magnetometer data cannot be reproduced by either model; therefore, we deform the force‐free model to show that small deformations can replicate these features. One such deformation is to use an elliptical cross section, which replicates a plateau in magnetic field strength along with asymmetries on either side of the center of the flux ropes. Additionally, we explore the properties of bending a flux rope, where we find that minimum variance analysis becomes increasingly degenerate with bending, along with a slight bend causing the switching of the axial field direction from intermediate to maximum variance direction. We conclude that the flux ropes at Titan show aspects of developing flux ropes, compared to other planetary bodies, which exhibit more agreement to the force‐free assumptions of mature flux ropes

Does greening of neotropical cities considerably mitigate carbon dioxide emissions? The case of Medellin, Colombia

Cities throughout the world are advocating highly promoted tree plantings as a climate change mitigation measure. Assessing the carbon offsets associated with urban trees relative to other climate change policies is vital for sustainable development, planning, and solving environmental and socio-economic problems, but is difficult in developing countries. We estimated and assessed carbon dioxide (CO2) storage, sequestration, and emission offsets by public trees in the Medellin Metropolitan Area, Colombia, as a viable Nature-Based Solution for the Neotropics. While previous studies have discussed nature-based solutions and explored urban tree carbon dynamics in high income countries, few have been conducted in tropical cities in low-middle income countries, particularly within South America. We used a public tree inventory for the Metropolitan Area of the Aburrá Valley and an available urban forest functional model, i-Tree Streets, calibrated for Colombia's context. We found that CO2 offsets from public trees were not as effective as cable cars or landfills. However, if available planting spaces are considered, carbon offsets become more competitive with cable cars and other air quality and socio-economic co-benefits are also provided. The use of carbon estimation models and the development of relevant carbon accounting protocols in Neotropical cities are also discussed. Our nature-based solution approach can be used to better guide management of urban forests to mitigate climate change and carbon offset accounting in tropical cities lacking available information. © 2017 by the authors

Ultrafast Spin Density Wave Transition in Chromium Governed by Thermalized Electron Gas

The energy and momentum selectivity of time- and angle-resolved photoemission spectroscopy is exploited to address the ultrafast dynamics of the antiferromagnetic spin density wave (SDW) transition photoexcited in epitaxial thin films of chromium. We are able to quantitatively extract the evolution of the SDW order parameter Δ through the ultrafast phase transition and show that Δ is governed by the transient temperature of the thermalized electron gas, in a mean field description. The complete destruction of SDW order on a sub-100 fs time scale is observed, much faster than for conventional charge density wave materials. Our results reveal that equilibrium concepts for phase transitions such as the order parameter may be utilized even in the strongly nonadiabatic regime of ultrafast photoexcitation

Cognitive behavioral therapy for insomnia comorbid with COPD is feasible with preliminary evidence of positive sleep and fatigue effects

Background: Many people with COPD report difficulties falling asleep or staying asleep, insufficient sleep duration, or nonrestorative sleep. Cognitive behavioral therapy for insomnia (CBT-I) has proved effective not only in people with primary insomnia but also in people with insomnia comorbid with psychiatric and medical illness (eg, depression, cancer, and chronic pain). However, CBT-I has rarely been tested in those with COPD who have disease-related features that interfere with sleep and may lessen the effectiveness of such therapies. The purpose of this study was to determine the feasibility of applying a CBT-I intervention for people with COPD and to assess the impact of CBT-I on insomnia severity and sleep-related outcomes, fatigue, mood, and daytime functioning. Methods: The study had two phases. In Phase 1, a 6-weekly session CBT-I intervention protocol in participants with COPD was assessed to examine feasibility and acceptability. Phase 2 was a small trial utilizing a prospective two-group pre- and post-test design with random assignment to the six-session CBT-I or a six-session wellness education (WE) program to determine the effects of each intervention, with both interventions being provided by a nurse behavioral sleep medicine specialist. Results: Fourteen participants (five in Phase 1 and nine in Phase 2) completed six sessions of CBT-I and nine participants completed six sessions of WE. Participants indicated that both interventions were acceptable. Significant positive treatment-related effects of the CBT-I intervention were noted for insomnia severity (P = 0.000), global sleep quality (P = 0.002), wake after sleep onset (P = 0.03), sleep efficiency (P = 0.02), fatigue (P = 0.005), and beliefs and attitudes about sleep (P = 0.000). Significant positive effects were noted for depressed mood after WE (P = 0.005). Conclusion: Results suggest that using CBT-I in COPD is feasible and the outcomes compare favorably with those obtained in older adults with insomnia in the context of other chronic illnesses