T-111 Rankine system corrosion test loop, volume 2

For abstract, see N76-18258

On-board processing for future satellite communications systems: Satellite-Routed FDMA

A frequency division multiple access (FDMA) 30/20 GHz satellite communications architecture without on-board baseband processing is investigated. Conceptual system designs are suggested for domestic traffic models totaling 4 Gb/s of customer premises service (CPS) traffic and 6 Gb/s of trunking traffic. Emphasis is given to the CPS portion of the system which includes thousands of earth terminals with digital traffic ranging from a single 64 kb/s voice channel to hundreds of channels of voice, data, and video with an aggregate data rate of 33 Mb/s. A unique regional design concept that effectively smooths the non-uniform traffic distribution and greatly simplifies the satellite design is employed. The satellite antenna system forms thirty-two 0.33 deg beam on both the uplinks and the downlinks in one design. In another design matched to a traffic model with more dispersed users, there are twenty-four 0.33 deg beams and twenty-one 0.7 deg beams. Detailed system design techniques show that a single satellite producing approximately 5 kW of dc power is capable of handling at least 75% of the postulated traffic. A detailed cost model of the ground segment and estimated system costs based on current information from manufacturers are presented

Universality in one-dimensional fermions at finite temperature: Density, pressure, compressibility, and contact

We present finite-temperature, lattice Monte Carlo calculations of the particle number density, compressibility, pressure, and Tan's contact of an unpolarized system of short-range, attractively interacting spin-1/2 fermions in one spatial dimension, i.e., the Gaudin-Yang model. In addition, we compute the second-order virial coefficients for the pressure and the contact, both of which are in excellent agreement with the lattice results in the low-fugacity regime. Our calculations yield universal predictions for ultracold atomic systems with broad resonances in highly constrained traps. We cover a wide range of couplings and temperatures and find results that support the existence of a strong-coupling regime in which the thermodynamics of the system is markedly different from the noninteracting case. We compare and contrast our results with identical systems in higher dimensions.Comment: 6 pages, 7 figures; improved, published versio

Flight test and evaluation of Omega navigation in a general aviation aircraft. Volume 2: Appendices

Detailed documentation for each flight of the Omega Flight Evaluation study is presented, including flight test description sheets and actual flight data plots. Computer programs used for data processing and flight planning are explained and the data formats utilized by the Custom Interface Unit are summarized

Near Infrared Spectroscopic Monitoring During Cardiopulmonary Exercise Testing Detects Anaerobic Threshold

Cardiopulmonary exercise testing (CPET) provides assessment of the integrative responses involving the pulmonary, cardiovascular, and skeletal muscle systems. Application of exercise testing remains limited to children who are able to understand and cooperate with the exercise protocol. Near-infrared spectroscopy (NIRS) provides a noninvasive, continuous method to monitor regional tissue oxygenation (rSO2). Our specific aim was to predict anaerobic threshold (AT) during CPET noninvasively using two-site NIRS monitoring. Achievement of a practical noninvasive technology for estimating AT will increase the compatibility of CPET. Patients without structural or acquired heart disease were eligible for inclusion if they were ordered to undergo CPET by a cardiologist. Data from 51 subjects was analyzed. The ventilatory anaerobic threshold (VAT) was computed on VCO2 and respiratory quotient post hoc using the standard V-slope method. The inflection points of the regional rSO2 time-series were identified as the noninvasive regional NIRS AT for each of the two monitored regions (cerebral and kidney). AT calculation made using an average of kidney and brain NIRS matched the calculation made by VAT for the same patient. Two-site NIRS monitoring of visceral organs is a predictor of AT

Meander, Folding and Arch Statistics

The statistics of meander and related problems are studied as particular realizations of compact polymer chain foldings. This paper presents a general discussion of these topics, with a particular emphasis on three points: (i) the use of a direct recursive relation for building (semi) meanders (ii) the equivalence with a random matrix model (iii) the exact solution of simpler related problems, such as arch configurations or irreducible meanders.Comment: 82 pages, uuencoded, uses harvmac (l mode) and epsf, 26+7 figures include

Stability of Inhomogeneous Superstructures from Renormalized Mean-field Theory of the t--J Model

Using the t--J model (which can also include Coulomb repulsion) and the ``plain vanilla'' renormalized mean-field theory of Zhang et al. (1988), stability of inhomogeneous 4a x 4a superstructures as those observed in cuprates superconductors around hole doping 1/8 is investigated. We find a non-uniform 4a x 4a bond order wave involving simultaneously small (~ 10^-2 t) inhomogeneous staggered plaquette currents as well as a small charge density modulation similar to pair density wave order. On the other hand, no supersolid phase involving a decoupling in the superconducting particle-particle channel is found.Comment: 4 page

Basic Representations of A_{2l}^(2) and D_{l+1}^(2) and the Polynomial Solutions to the Reduced BKP Hierarchies

Basic representations of A_{2l}^(2) and D_{l+1}^(2) are studied. The weight vectors are represented in terms of Schur's $Q$-functions. The method to get the polynomial solutions to the reduced BKP hierarchies is shown to be equivalent to a certain rule in Maya game.Comment: January 1994, 11 page

Ultrahigh Transmission Optical Nanofibers

We present a procedure for reproducibly fabricating ultrahigh transmission optical nanofibers (530 nm diameter and 84 mm stretch) with single-mode transmissions of 99.95 $\pm$ 0.02%, which represents a loss from tapering of 2.6 $\,\times \,$ 10$^{-5}$ dB/mm when normalized to the entire stretch. When controllably launching the next family of higher-order modes on a fiber with 195 mm stretch, we achieve a transmission of 97.8 $\pm$ 2.8%, which has a loss from tapering of 5.0 $\,\times \,$ 10$^{-4}$ dB/mm when normalized to the entire stretch. Our pulling and transfer procedures allow us to fabricate optical nanofibers that transmit more than 400 mW in high vacuum conditions. These results, published as parameters in our previous work, present an improvement of two orders of magnitude less loss for the fundamental mode and an increase in transmission of more than 300% for higher-order modes, when following the protocols detailed in this paper. We extract from the transmission during the pull, the only reported spectrogram of a fundamental mode launch that does not include excitation to asymmetric modes; in stark contrast to a pull in which our cleaning protocol is not followed. These results depend critically on the pre-pull cleanliness and when properly following our pulling protocols are in excellent agreement with simulations.Comment: 32 pages, 10 figures, accepted to AIP Advance