3,774 research outputs found
Lightweight pressurization system for the Apollo service propulsion system Final report
Lightweight cryogenic He cascade pressurization concept for Apollo service propulsion syste
Observations on the vibration of axially-tensioned elastomeric pipes conveying fluids
A study of the effect of axial tension on the vibration of a single-span elastomeric pipe clamped at both ends conveying fluid has been carried out both experimentally and theoretically. A new mathematical model using a penalty function technique and the method of kinematic correction and fictitious loads has been developed. The influence of flowing fluid and axial tension on natural frequencies and mode shapes of the system has been described using this model and compared with experimental observations. Linear and non-linear dynamic response of the harmonically excited pipe has also been investigated for varying flow velocities and initial axial tensions
Orbital assembly and maintenance study
The requirements, conceptual design, tradeoffs, procedures, and techniques for orbital assembly of the support structure of the microwave power transmission system and the radio astronomy telescope are described. Thermal and stress analyses, packaging, alignment, and subsystems requirements are included along with manned vs. automated and transportation tradeoffs. Technical and operational concepts for the manned and automated maintenance of satellites were investigated and further developed results are presented
Charge-qubit operation of an isolated double quantum dot
We have investigated coherent time evolution of pseudo-molecular states of an
isolated (leadless) silicon double quantum-dot, where operations are carried
out via capacitively-coupled elements. Manipulation is performed by short
pulses applied to a nearby gate, and measurement is performed by a
single-electron transistor. The electrical isolation of this qubit results in a
significantly longer coherence time than previous reports for semiconductor
charge qubits realized in artificial molecules.Comment: 4 journal pages, 4 figures, Lette
Techniques for Consecutive TEM and Atom Probe Tomography Analysis of Nanowires
Nanowires show great promise for development in many technological applications including electronics, photonics, and displays . Due to the fine scale of nanowires, transmission electron microscopy (TEM) and atom probe tomography (APT) are among a limited number of techniques that can measure the crystallographic and chemical nature of these structures which ultimately define their performance
Techniques for Consecutive TEM and Atom Probe Tomography Analysis of Nanowires
Nanowires show great promise for development in many technological applications including electronics, photonics, and displays . Due to the fine scale of nanowires, transmission electron microscopy (TEM) and atom probe tomography (APT) are among a limited number of techniques that can measure the crystallographic and chemical nature of these structures which ultimately define their performance
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