Second Harmonic Generation in Proton-Exchanged Lithium Niobate Optical Waveguides

Abstract Not Provided

A Tale of Two Tilings

What do you get when you cross a crystal with a quasicrystal? The surprising answer stretches from Fibonacci to Kepler, who nearly 400 years ago showed how the ancient tiles of Archimedes form periodic patterns.Comment: 3 pages, 1 figur

Rotary-wing aerodynamics. Volume 2: Performance prediction of helicopters

Application of theories, as well as, special methods of procedures applicable to performance prediction are illustrated first, on an example of the conventional helicopter and then, winged and tandem configurations. Performance prediction of conventional helicopters in hover and vertical ascent are investigated. Various approaches to performance prediction in forward translation are presented. Performance problems are discussed only this time, a wing is added to the baseline configuration, and both aircraft are compared with respect to their performance. This comparison is extended to a tandem. Appendices on methods for estimating performance guarantees and growth of aircraft concludes this volume

Development of a Simulation Framework for CubeSat Performance Modeling

Space systems are notoriously difficult to develop due to the nature of the environment in which they must operate. Designers have only a limited window to ensure systems will function as intended, placing a high importance on testing. This paper discussed the ongoing development of a simulation framework to support Hardware-in-the-Loop (HIL) testing of CubeSat subsystem hardware. This work is being conducted at the Air Force Institute of Technology (AFIT) in support of the institution’s CubeSat program. The simulation framework is organized into the classic spacecraft subsystems. Each of these subsystems will support a software model and interfaces for the integration of flight hardware into the simulation framework. In demonstration of this concept, propulsion hardware has been successfully integrated into the model environment. Telemetry reception and command transmission within the simulation framework is functional and demonstrated. A loop containing the propulsion hardware, simple controller, and orbital motion propagator was developed to demonstrate the HIL test functionality of the simulation framework. This focus on the development of the propulsion HIL test configuration is a point of distinction from other HIL simulations, which typically focus on the Attitude Determination and Control System (ADCS). Presented results validate successful integration of propulsion subsystem hardware into the simulation framework. Future work will focus on the integration of CubeSat subsystem models into the framework

The Rend Lake fault system in southern Illinois

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PCR-based method for targeting 16S-23S rRNA intergenic spacer regions among Vibrio species

<p>Abstract</p> <p>Background</p> <p>The genus <it>Vibrio </it>is a diverse group of Gram-negative bacteria comprised of 74 species. Furthermore, the genus has and is expected to continue expanding with the addition of several new species annually. Consequently, it is of paramount importance to have a method which is able to reliably and efficiently differentiate the numerous <it>Vibrio </it>species.</p> <p>Results</p> <p>In this study, a novel and rapid polymerase chain reaction (PCR)-based intergenic spacer (IGS)-typing system for vibrios was developed that is based on the well-known IGS regions located between the 16S and 23S rRNA genes on the bacterial chromosome. The system was optimized to resolve heteroduplex formation as well as to take advantage of capillary gel electrophoresis technology such that reproducible analyses could be achieved in a rapid manner. System validation was achieved through testing of 69 archetypal <it>Vibrio </it>strains, representing 48 <it>Vibrio </it>species, from which an 'IGS-type' profile database was generated. These data, presented here in several cluster analyses, demonstrated successful differentiation of the 69 type strains showing that this PCR-based fingerprinting method easily discriminates bacterial strains at the species level among <it>Vibrio</it>. Furthermore, testing 36 strains each of <it>V. parahaemolyticus </it>and <it>V. vulnificus</it>, important food borne pathogens, isolated from a variety of geographical locations with the IGS-typing method demonstrated distinct IGS-typing patterns indicative of subspecies divergence in both populations making this technique equally useful for intraspecies differentiation, as well.</p> <p>Conclusion</p> <p>This rapid, reliable and efficient IGS-typing system, especially in combination with 16S rRNA gene sequencing, has the capacity to not only discern and identify vibrios at the species level but, in some cases, at the sub-species level, as well. This procedure is particularly well-suited for preliminary species identification and, lends itself nicely to epidemiological investigations providing information more quickly than other time-honoured methods traditionally used in these types of analyses.</p

EOS-AM1 Nickel Hydrogen Cell Interim Life Test Report

This paper reports the interim results Earth Observing System AM-1 project (EOS-AM-1) nickel hydrogen cell life test being conducted under contract to National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) at the Lockheed Martin Missiles and Space (LMMS) facility in East Windsor, NJ; and at COMSAT Labs., Clarksburg, MD. The purpose of the tests is to verify that the EOS-AM-1 cell design can meet five years of real-time Low Earth Orbit (LEO) cycling. The tests include both real-time LEO and accelerated stress tests. At LMMS, the first real-time LEO simulated 99 minute orbital cycle started on February 7, 1994 and the test has been running continuously since that time, with 18202 LEO cycles completed as of September 1, 1997. Each cycle consists of a 64-minute charge (VT at 1,507 volts per cell, 1.06 C/D ratio, followed by 0.6 ampere trickle charge) and a 35 minute constant power discharge at 177 watts (22.5 percent DOD). At COMSAT, the accelerated stress test consists of 90 minute orbital cycles at 60 percent DOD with a 30 minute discharge at 60 amperes and a 60 minute charge at 40 amperes (VT at 1.54 volts per cell to 1.90 C/D ratio, followed by 0.6 ampere trickle charge). The real-time LEO life test battery consists of seven, 50AH (nameplate rating) Eagle-Picher, Inc. (EPI) Mantech cells manufactured into three, 3-cell pack assemblies (there are two place holder cells that are not part of the life test electrical circuit). The test pack is configured to simulate the conductive thermal design of the spacecraft battery, including: conductive aluminum sleeves, 3-cell pack aluminum baseplate, and honeycomb panel all mounted to a liquid (minus 5 deg) cold plate. The entire assembly is located in a thermal chamber operating at plus 3 deg. The accelerated stress test unit consists of five cells mounted in machined aluminum test sleeves and is operating at plus 10 deg. The real-time LEO life test battery has met all performance requirements through the first 18,202 cycles, including: end of charge and discharge cell voltages and voltage gradients; end of charge and discharge cells pressures; within cell and between cell temperature gradients dischare capacity; current and power levels; and all charge parameters. The accelerated stress test battery has completed 11998 cycles when the test was terminated. The stress test unit met all test parameters. This paper reports battery performances as a function of cycle life for both the real-time LEO and the accelerated life test regimes

Panel Discussion On Lipid Metabolism In Cardiovascular Disease†

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/111126/1/jgs00741.pd