Comparison of approximate and numerical analyses of nonlinear combustion instability

At the present time, there are three general analytical techniques available to study problems of unsteady motions in rocket motors: linear stability analysis; approximate nonlinear analysis, founded on examining the behavior of coupled normal modes; and numerical calculations based on the conservation equations for one-dimensional flows. The last two yield the linear results as a limit. It is the main purpose of this paper to check the accuracy of the approximate analysis against the numerical analysis for some special cases. The results provide some justification for using the approximate analysis to study three dimensional problems

Transonic flow in a converging-diverging nozzle Final report

Transonic equations of motion for convergent-divergent nozzl

Suboptimal filtering. Part 2 - Compensation for modeling errors in orbit determination problems Final report

Compensation for dynamic and measurement model errors in real time orbit determination system

Interactions of technology and society: Impacts of improved airtransport. A study of airports at the grass roots

The feasibility of applying a particular conception of technology and social change to specific examples of technological development was investigated. The social and economic effects of improved airport capabilities on rural communities were examined. Factors which led to the successful implementation of a plan to construct sixty small airports in Ohio are explored and implications derived for forming public policies, evaluating air transportation development, and assessing technology

A model to promote activity competence in elders.

This paper describes an occupational therapy home-based intervention in which purposeful activities were used to promote adaptation and competence in older adults with chronic disabilities. Seven home care therapists visited 17 randomly selected, community-living elders who were chronically disabled and who volunteered to participate in the program. The number of visits ranged from 3 to 10 and occurred over a 3-month period according to clients\u27 needs and wishes. Therapists enhanced their ability to enter the client\u27s social and cultural system by using participant-observation techniques and collaboratively identified activities. Therapists documented each home visit with a structured fieldnote form. An analysis of 112 field-notes indicated that therapists were able to understand a client\u27s needs; this understanding resulted in small qualitative gains in areas identified as important by the client. Reilly\u27s concept of an activity continuum was a useful framework from which to work with this population. The implications for program development, treatment outcomes, and accountability with this approach promote improved future treatment planning with the elderly with chronic disability

Home adaptations for persons with chronic disabilities: an educational model.

This paper offers a method by which to train students in the provision of culturally relevant, in-home environmental adaptations for persons with chronic disabilities. On the basis of a theoretical framework, the student therapist learns about the client\u27s life-style and offers adaptations that evolve from a collaborative problem-solving process. The training process has been developed and refined over a 3-year period. A case study illustrates the student\u27s application of theory and practice and the outcome for the client of this service provision approach

Quantum Versus Mean Field Behavior of Normal Modes of a Bose-Einstein Condensate in a Magnetic Trap

Quantum evolution of a collective mode of a Bose-Einstein condensate containing a finite number N of particles shows the phenomena of collapses and revivals. The characteristic collapse time depends on the scattering length, the initial amplitude of the mode and N. The corresponding time values have been derived analytically under certain approximation and numerically for the parabolic atomic trap. The revival of the mode at time of several seconds, as a direct evidence of the effect, can occur, if the normal component is significantly suppressed. We also discuss alternative means to verify the proposed mechanism.Comment: minor corrections are introduced into the tex

Spectral properties of the X-ray binary pulsar LMC X-4 during different intensity states

We present spectral variations of the binary X-ray pulsar LMC X-4 observed with the RXTE/PCA during different phases of its 30.5 day long third period. Only out of eclipse data were used for this study. The 3-25 keV spectrum, modeled with high energy cut-off power-law and iron line emission is found to show strong dependence on the intensity state. Correlations between the Fe line emission flux and different parameters of the continuum are presented here.Comment: 4 pages, 4 figure

Wave Mechanics of a Two Wire Atomic Beamsplitter

We consider the problem of an atomic beam propagating quantum mechanically through an atom beam splitter. Casting the problem in an adiabatic representation (in the spirit of the Born-Oppenheimer approximation in molecular physics) sheds light on explicit effects due to non-adiabatic passage of the atoms through the splitter region. We are thus able to probe the fully three dimensional structure of the beam splitter, gathering quantitative information about mode-mixing, splitting ratios,and reflection and transmission probabilities