11,159 research outputs found

    Computer integration of hydrodynamics equations for heat pipes

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    Program has five operational modes that provide user flexibility in answering crucial heat-pipe design questions. User specifies heat input and rejection distribution

    User's manual for the TRW gaspipe program. A vapor-gas front analysis program for heat pipes containing noncondensible gas

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    Digital computer program manual for design, analysis, and performance prediction of heat pipes with noncondensible gases including input/output routines and Runge-Kutta model

    Variable conductance heat pipe technology

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    Research and development programs in variable conductance heat pipe technology were conducted. The treatment has been comprehensive, involving theoretical and/or experimental studies in hydrostatics, hydrodynamics, heat transfer into and out of the pipe, fluid selection, and materials compatibility, in addition to the principal subject of variable conductance control techniques. Efforts were not limited to analytical work and laboratory experimentation, but extended to the development, fabrication and test of spacecraft hardware, culminating in the successful flight of the Ames Heat Pipe Experiment on the OAO-C spacecraft

    User's manual for the TRW gaspipe 2 program: A vapor-gas front analysis program for heat pipes containing non-condensible gas

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    A digital computer program for design and analysis of heat pipes which contain non-condensible gases, either for temperature control or to aid in start-up from the frozen state, is presented. Some of the calculations which are possible with the program are: (1) wall temperature profile along a gas-loaded heat pipe, (2) amount of gas loading necessary to obtain desired evaporator temperature at a desired heat load, (3) heat load versus evaporator temperature for a fixed amount of gas in the pipe, and (4) heat and mass transfer along the pipe, including the vapor-gas front region

    The Arabidopsis JAGGED gene encodes a zinc finger protein that promotes leaf tissue development

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    Important goals in understanding leaf development are to identify genes involved in pattern specification, and also genes that translate this information into cell types and tissue structure. Loss-of-function mutations at the JAGGED (JAG) locus result in Arabidopsis plants with abnormally shaped lateral organs including serrated leaves, narrow floral organs, and petals that contain fewer but more elongate cells. jag mutations also suppress bract formation in leafy, apetala1 and apetala2 mutant backgrounds. The JAG gene was identified by map-based cloning to be a member of the zinc finger family of plant transcription factors and encodes a protein similar in structure to SUPERMAN with a single C2H2-type zinc finger, a proline-rich motif and a short leucine-rich repressor motif. JAG mRNA is localized to lateral organ primordia throughout the plant but is not found in the shoot apical meristem. Misexpression of JAG results in leaf fusion and the development of ectopic leaf-like outgrowth from both vegetative and floral tissues. Thus, JAG is necessary for proper lateral organ shape and is sufficient to induce the proliferation of lateral organ tissue

    In-vivo magnetic resonance imaging of hyperpolarized silicon particles

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    Silicon-based micro and nanoparticles have gained popularity in a wide range of biomedical applications due to their biocompatibility and biodegradability in-vivo, as well as a flexible surface chemistry, which allows drug loading, functionalization and targeting. Here we report direct in-vivo imaging of hyperpolarized 29Si nuclei in silicon microparticles by MRI. Natural physical properties of silicon provide surface electronic states for dynamic nuclear polarization (DNP), extremely long depolarization times, insensitivity to the in-vivo environment or particle tumbling, and surfaces favorable for functionalization. Potential applications to gastrointestinal, intravascular, and tumor perfusion imaging at sub-picomolar concentrations are presented. These results demonstrate a new background-free imaging modality applicable to a range of inexpensive, readily available, and biocompatible Si particles.Comment: Supplemental Material include

    Variable Conductance Heat Pipe Technology

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    A research and development program in variable conductance heat pipe technology is reported. The project involved: (1) theoretical and/or experimental studies in hydrostatics, (2) hydrodynamics, (3) heat transfer into and out of the pipe, (4) fluid selection, and (5) materials compatibility. The development, fabrication, and test of the space hardware resulted in a successful flight of the heat pipe experiment on the OAO-3 satellite. A summary of the program is provided and a guide to the location of publications on the project is included

    Exercise behavior change and the effect of lost resources

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    This study was designed to assess the effects of lost resources on exercise behavior among a sample of 30 foreign exchange students who were identified as having experienced a relapse in their level of physical activity. The first phase of the study was longitudinal in nature, comparing baseline data collected from a sample of 110 exchange students from Malaysia on their initial arrival in England with data collected from the same sample 4 months later. Results of a multivariate analysis of variance indicated a significant effect for scores on processes of change, self-efficacy, and decisional balance, F(12, 18) = 12.74, p less than .001. Subsequent examination of univariate F values also revealed significant differences for self-reevaluation, reinforcement management, self-liberation, and self-efficacy. Results from the second phase of the study, which qualitatively assessed the relationship between reductions in physical activity and personal/material resources, revealed that exercise behavior was significantly influenced by resources lost as a result of being in an unfamiliar environment. Implications for health promotion practitioners and researchers are discussed
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