Centaur in-tank explosion flow fields within STS and Titan 4 payload spaces

Explosions are examined which result from the mixing of liquid hydrogen and liquid oxygen (LH2-LO2) such that the reactants are confined by the missile (CBM) body. Explosion which were confined by the ground surface (CBGS) were also studied, with results reported elsewhere. Initial attempts to predict the reported PYRO experimental results were unsuccessful. A new reaction energy addition hypothesis was then developed and tested. The results obtained provide reasonable agreement with the experiments both in the near and far field. Calculations were performed to predict the environment which would occur at the Galileo Radioisotope Thermoelectric Generator (RTG) location given a Centaur G' upper stage and an STS launch vehicle. It was concluded that the principle threat to the RTG in this environment would be the impact of a slug of LH2. No analyses were conducted to assess the response of the Galileo RTG to such an environment. It was shown that the flow field resulting from the failure of the Centaur G' tankage was benign. It was concluded that while the cryogen particle velocity was very high, the flow field density was extremely low. As a result, the dynamic pressure was a trivial eight psia

Summary of miscellaneous hazard environments for hypothetical Space Shuttle and Titan IV launch abort accidents

The various analyses described here were aimed at obtaining a more comprehensive understanding and definition of the environments in the vicinity of the Radioisotope Thermal Generator (RTG) during certain Space Transportation System (STS) and Titan IV launch abort accidents. Addressed here are a number of issues covering explosion environments and General Purpose Heat Source Radioisotope Thermoelectric Generator (GPHS-RTG) responses to those environments

On the nature of the fragment environment created by the range destruction or random failure of solid rocket motor casings

Given here are predictions of fragment velocities and azimuths resulting from the Space Transportation System Solid Rocket Motor range destruct, or random failure occurring at any time during the 120 seconds of Solid Rocket Motor burn. Results obtained using the analytical methods described showed good agreement between predictions and observations for two specific events. It was shown that these methods have good potential for use in predicting the fragmentation process of a number of generically similar casing systems. It was concluded that coupled Eulerian-Lagrangian calculational methods of the type described here provide a powerful tool for predicting Solid Rocket Motor response

The Schwinger SU(3) Construction - II: Relations between Heisenberg-Weyl and SU(3) Coherent States

The Schwinger oscillator operator representation of SU(3), studied in a previous paper from the representation theory point of view, is analysed to discuss the intimate relationships between standard oscillator coherent state systems and systems of SU(3) coherent states. Both SU(3) standard coherent states, based on choice of highest weight vector as fiducial vector, and certain other specific systems of generalised coherent states, are found to be relevant. A complete analysis is presented, covering all the oscillator coherent states without exception, and amounting to SU(3) harmonic analysis of these states.Comment: Latex, 51 page

Relativistic Operator Description of Photon Polarization

We present an operator approach to the description of photon polarization, based on Wigner's concept of elementary relativistic systems. The theory of unitary representations of the Poincare group, and of parity, are exploited to construct spinlike operators acting on the polarization states of a photon at each fixed energy momentum. The nontrivial topological features of these representations relevant for massless particles, and the departures from the treatment of massive finite spin representations, are highlighted and addressed.Comment: Revtex 9 page

The Schwinger SU(3) construction - I: Multiplicity problem and relation to induced representations

The Schwinger oscillator operator representation of SU(3) is analysed with particular reference to the problem of multiplicity of irreducible representations. It is shown that with the use of an $Sp(2,R)$ unitary representation commuting with the SU(3) representation, the infinity of occurrences of each SU(3) irreducible representation can be handled in complete detail. A natural `generating representation' for SU(3), containing each irreducible representation exactly once, is identified within a subspace of the Schwinger construction; and this is shown to be equivalent to an induced representation of SU(3).Comment: Latex, 25 page

Landau Levels in the noncommutative AdS2AdS_2

We formulate the Landau problem in the context of the noncommutative analog of a surface of constant negative curvature, that is $AdS_2$ surface, and obtain the spectrum and contrast the same with the Landau levels one finds in the case of the commutative $AdS_2$ space.Comment: 19 pages, Latex, references and clarifications added including 2 figure

The direct simulation of high-speed mixing-layers without and with chemical heat release

A direct numerical simulation of high speed reacting and non-reacting flows for H2-air systems is presented. The calculations are made for a convective Mach number of 0.38 with hyperbolic tangent initial profile and finite rate chemical reactions. A higher-order numerical method is used in time accurate mode to time advance the solution to a statistical steady state. About 600 time slices of all the variables are then stored for statistical analysis. It is shown that most of the problems of high-speed combustion with air are characterized by relatively weak heat release. The present study shows that: (1) the convective speed is reduced by heat release by about 10 percent at this convective Mach number M(sub c) = 0.38; (2) the variation of the mean and rms fluctuation of temperature can be explained on the basis of temperature fluctuation between the flame temperature and the ambient; (3) the growth rate with heat release is reduced by 7 percent; and (4) the entrainment is reduced by 25 percent with heat release. These differences are small in comparison with incompressible flow dynamics, and are argued to be due to the reduced importance of heat release in comparison with the large enthalpy gradients resulting from the large-scale vortex dynamics. It is finally suggested that the problems of reduced mixing in high-speed flows are not severely complicated by heat release

Mesoscopic Transport: The Electron-Gas Sum Rules in a Driven Quantum Point Contact

The nature of the electron gas is characterized, above all, by its multi-particle correlations. The conserving sum rules for the electron gas have been thoroughly studied for many years, and their centrality to the physics of metallic conduction is widely understood (at least in the many-body community). We review the role of the conserving sum rules in mesoscopic transport, as normative criteria for assessing the conserving status of mesoscopic models. In themselves, the sum rules are specific enough to rule out any such theory if it fails to respect the conservation laws. Of greater interest is the capacity of the compressibility sum rule, in particular, to reveal unexpected fluctuation effects in nonuniform mesoscopic structures.Comment: TeX, 11pp, no fi

Photoplethysmography

The process of breathing occurs as a physiological cycle in which one nasal cavity is functionally active while the other is resting, i.e., breathing alternates between the nostrils according to a regular pattern referred to as the "nasal cycle" and this cycle has been found to have a profound effect on a number of brain functions. It is suspected that some cross coupling exists between the dominant nostril and the active cerebral hemisphere. It is believed that breathing has a profound effect on man's physical/psychological functioning and is the link between the body and the mind. Pranayama is a well-proven technique for controlled rhythmic breathing with beneficial effects reported both for the body and the mind. In this study the arterial blood volumetric changes from 10 normal breathing subjects and 30 subjects practicing pranayama are monitored non-invasively at the earlobes using optical sensors. This method is known as Photoplethysmography (PPG). Spectral analysis and Heart Rate Variability (HRV) studies are performed on the collected PPG data. The results show fundamental changes in the spectral components of the PPG signal in relation to the breathing brought about by pranayama. In addition, a bi-nasal respiratory airflow monitor is designed and developed for this study utilizing miniature thermistors that can be introduced into the two nostrils of the subject without causing discomfort to the subject. Another study is also reported in which changes in microcirculation in chakra points were studies as a result of concentration on these points. Results indicate the low frequency component around 0.18 Hz changes dramatically during these procedures. Concentration on heart increases the amplitude of the low frequency by about 4.5 times. Concentration on the eyebrow chakra increases the value of this component by about 3 times, but the curve is much broader showing more "power" in that band of frequencies. Since prana or chi is related to amount of blood flow, it is likely the increase in microcirculation is related to increase in prana, as suggested in ancient texts. Further work is contemplated to peruse this line of thinking through standard clinical methods