793 research outputs found
Access flight hardware design and development
Several items were found to be of immense value in the design and development of the Assembly Concept for Construction of Erectable Space Structures (ACCESS) hardware. The early availability of mock-up and engineering test hardware helped to develop the concept and prove the feasibility of the experiment. The extensive neutral buoyancy testing was invaluable in developing the procedures and timelines, proving that the hardware functioned as intended, and effectively trained the astronauts. The early involvement of the crew systems/astronaut personnel was extremely beneficial in shaping the design to meet the EVA compatibility requirements. Also, the early definition of coupled loads and on-orbit dynamic responses can not be overemphasized due to the relative uncertainty in the magnitude of these loads and their impact on the design
Cocrystal formation by Ionic liquid-assisted grinding: Case study with cocrystals of caffeine
iquid assisted grinding using imidazolium-based ionic liquids (IL-AG) was found to be effective in isolation of cocrystals and cocrystal polymorphs. Isolation of specific polymorphs of caffeine–citric acid (CAF–CA) and caffeine–glutaric acid (CAF–GLU) cocrystals highlights the tunability of ILs in polymorphic control
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A New Class of Solvents for TRU Dissolution and Separation: Ionic Liquids
Through the current EMSP funding, solvent extraction technologies based on liquid-liquid partitioning of TRU to an Ionic Liquid phase containing conventional complexants has been shown to be viable. The growing understanding of the role that the different components of an ionic liquid can have on the partitioning mechanism, and on the nature of the subsequent dissolved species indicates strongly that ionic liquids are not necessarily direct replacements for volatile or otherwise hazardous organic solvents. Separations and partitioning can be exceptionally complex with competing solvent extraction, cation, anion and sacrificial ion exchange mechanisms are all important, depending on the selection of components for formation of the ionic liquid phase, and that control of these competing mechanisms can be utilized to provide new, alternative separations schemes
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A New Class of Solvents for TRU Dissolution and Separation: Ionic Liquids
Progress on the study of a New Class of Solvents for TRU Dissolution and Separation: Ionic Liquids is summarized under the headings of the major proposal objectives
Agarose processing in protic and mixed protic–aprotic ionic liquids : dissolution, regeneration and high conductivity, high strength ionogels
We have shown that low viscosity alkyl or hydroxyalkyl ammonium formate (ILs) can dissolve agarose, and higher dissolution can be achieved in the mixed, alkyl or hydroxyalkyl ammonium + imidazolium or pyridinium ILs. The polarity parameters α, β, π*, ET(30) and ETN of these IL systems were measured to explain their dissolution ability for agarose. Dissolved agarose was either regenerated using methanol as a precipitating solvent or ionogels were formed by cooling the agarose–IL solutions to ambient temperature. Exceptionally high strength ionogels were obtained from the agarose solutions in N-(2-hydroxyethyl)-ammonium formate or its mixture with 1-butyl-3-methylimidazolium chloride. Regenerated material and ionogels are characterized for their possible degradation/conformational changes and gel properties (thermal hysteresis, strength, viscoelasticity and conductivity) respectively. A high strength, high conducting ionogel was demonstrated to be able to build an electrochromic window. Such ionogels can also be utilized for other soft matter electronic devices and biomedical applications
The A Priori Design and Selection of Ionic Liquids as Solvents for Active Pharmaceutical Ingredients
Spin driven emergent antiferromagnetism and metal insulator transition in nanoscale p-Si
The entanglement of the charge, spin and orbital degrees of freedom can give
rise to emergent behavior especially in thin films, surfaces and interfaces.
Often, materials that exhibit those properties require large spin orbit
coupling. We hypothesize that the emergent behavior can also occur due to spin,
electron and phonon interactions in widely studied simple materials such as Si.
That is, large intrinsic spin-orbit coupling is not an essential requirement
for emergent behavior. The central hypothesis is that when one of the specimen
dimensions is of the same order (or smaller) as the spin diffusion length, then
non-equilibrium spin accumulation due to spin injection or spin-Hall effect
(SHE) will lead to emergent phase transformations in the non-ferromagnetic
semiconductors. In this experimental work, we report spin mediated emergent
antiferromagnetism and metal insulator transition in a Pd (1 nm)/Ni81Fe19 (25
nm)/MgO (1 nm)/p-Si (~400 nm) thin film specimen. The spin-Hall effect in p-Si,
observed through Rashba spin-orbit coupling mediated spin-Hall
magnetoresistance behavior, is proposed to cause the spin accumulation and
resulting emergent behavior. The phase transition is discovered from the
diverging behavior in longitudinal third harmonic voltage, which is related to
the thermal conductivity and heat capacity.Comment: 34 pages, Physica Status Solidi B- Physics, 201
Preventing Perinatal Transmission of HIV Costs and Effectiveness of a Recommended Intervention
In the United States, nearly all new human immunodeficiency virus (HIV) infections in children are acquired through perinatal (mother-to-infant) transmission. Each year, approximately 7000 infants are born to HIV-infected women in the United States.1 Without intervention, an estimated 15-30% of these infants would become infected.2 In 1994, results of the AIDS Clinical Trial Group (ACTG) Protocol 076 showed that treatment of infected pregnant women and their infants with zidovudine (ZDV) reduced the rate of perinatal HIV transmission from 25% to 8%.3,4 Following these findings, the Public Health Service (PHS) issued recommendations for ZDV therapy to prevent perinatal HIV transmission5 and for HIV counseling and voluntary testing of pregnant women.
Disseminating an Evidence-Based Course to Teach Self-Management of Auditory Hallucinations
This multi-site project extended course dissemination of the 10-session Behavioral Management of Auditory Hallucinations Course to U.S. Department of Veterans Affairs (VA) mental health outpatient settings. The VA Quality Enhancement Research Initiative (QUERI) model and Rogers\u27 theory of diffusion of innovations served as the theoretical framework. The course was taught to mental health professionals using teleconferencing, electronic media, and monthly conference calls across 24 VA mental health outpatient sites. Twenty course leaders provided feedback. One hundred percent reported being better able to communicate with patients about their voices and 96% reported improved understanding of the voice-hearing experience. Thirty-three course participants provided feedback. Ninety-four percent would recommend the course, 85% reported being better able to communicate with staff about their voices, and 66% reported being better able to manage their voices. Facilitators and barriers to course implementation are described
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