4,567 research outputs found
The performance of NASA research hydrogen masers
Field operable hydrogen masers based on prior maser designs are presented. These units incorporate improvements in magnetic shielding, lower noise electronics, better thermal control, and have a microprocessor for operation, monitoring, and diagnostic functions. They are ruggedly built for transportability and ease of service anywhere in the world
Pressure ramp programmer; IMBLMS Phase B4 Additional Tasks: Task 3.0 pressure ramp programmer
A pressure ramp programmer model was designed, fabricated and tested. This model, in conjunction with an automatic blood pressure monitor, automatically controls the pressure in the blood pressure monitor arterial cuff. The cuff pressurization cycle is designed to maximize accuracy and repeatability of blood pressure measurements. The key feature of this automatic cycle is rapid blood pressure cuff bleed down from an initial setting until systolic (diastolic) pressure is encountered followed by a short repressurization and slow bleed, long enough to permit accurate systolic (diastolic) pressure determination. The system includes a pressure reservoir which bleeds the cuff through a precision needle valve; a solenoid valve which permits rapid pressurization from the reservoir; and a pressure sensor which provides information for bleed rate and set point controls. Korotkoff sound signals from a microphone in the blood pressure cuff (not part of the system) provide decision information to the digital control system. The system completed a series of engineering tests using simulated Korotkoff sound inputs. The system performed successfully in all cases and was stable over an extended period of time
Natural Slow-Roll Inflation
It is shown that the non-perturbative dynamics of a phase change to the
non-trivial phase of -theory in the early universe can give
rise to slow-rollover inflation without recourse to unnaturally small
couplings.Comment: 14 LaTex pages (3 figures available on request), UNITUE-THEP-15-199
Comparison of selected submicron powder blending methods for dispersion alloys
Wet and dry blending nickel-aluminum oxide submicron powders for dispersion-strengthened alloy
Asymptotic freedom in a scalar field theory on the lattice
An alternative model to the trivial -theory of the standard model of
weak interactions is suggested, which embodies the Higgs-mechanism, but is free
of the conceptual problems of standard -theory. We propose a
N-component, O(N)-symmetric scalar field theory, which is originally defined on
the lattice. The model can be motivated from SU(2) gauge theory. Thereby the
scalar field arises as a gauge invariant degree of freedom. The scalar lattice
model is analytically solved in the large N limit. The continuum limit is
approached via an asymptotically free scaling. The renormalized theory evades
triviality, and furthermore gives rise to a dynamically formed mass of the
scalar particle.Comment: 10 pages, LaTeX, one figure and a motivation for the particular type
of action adde
Modulational Instability and Complex Dynamics of Confined Matter-Wave Solitons
We study the formation of bright solitons in a Bose-Einstein condensate of
Li atoms induced by a sudden change in the sign of the scattering length
from positive to negative, as reported in a recent experiment (Nature {\bf
417}, 150 (2002)). The numerical simulations are performed by using the 3D
Gross-Pitaevskii equation (GPE) with a dissipative three-body term. We show
that a number of bright solitons is produced and this can be interpreted in
terms of the modulational instability of the time-dependent macroscopic wave
function of the Bose condensate. In particular, we derive a simple formula for
the number of solitons that is in good agreement with the numerical results of
3D GPE. By investigating the long time evolution of the soliton train solving
the 1D GPE with three-body dissipation we find that adjacent solitons repel
each other due to their phase difference. In addition, we find that during the
motion of the soliton train in an axial harmonic potential the number of
solitonic peaks changes in time and the density of individual peaks shows an
intermittent behavior. Such a complex dynamics explains the ``missing
solitons'' frequently found in the experiment.Comment: to be published in Phys. Rev. Let
Urine sampling and collection system
This specification defines the performance and design requirements for the urine sampling and collection system engineering model and establishes requirements for its design, development, and test. The model shall provide conceptual verification of a system applicable to manned space flight which will automatically provide for collection, volume sensing, and sampling of urine
Corporate Social Responsibility Through an Economic Lens
Business leaders, government officials, and academics are focusing considerable attention on the concept of “corporate social responsibility” (CSR), particularly in the realm of environmental protection. Beyond complete compliance with environmental regulations, do firms have additional moral or social responsibilities to commit resources to environmental protection? How should we think about the notion of firms sacrificing profits in the social interest? May they do so within the scope of their fiduciary responsibilities to their shareholders? Can they do so on a sustainable basis, or will the forces of a competitive marketplace render such efforts and their impacts transient at best? Do firms, in fact, frequently or at least sometimes behave this way, reducing their earnings by voluntarily engaging in environmental stewardship? And finally, should firms carry out such profit-sacrificing activities (i.e., is this an efficient use of social resources)? We address these questions through the lens of economics, including insights from legal analysis and business scholarship.corporate social responsibility, voluntary environmental performance
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