Liquid oxygen/liquid hydrogen auxiliary power system thruster investigation

The design, fabrication, and demonstration of a 111 newton (25 lb) thrust, integrated auxiliary propulsion system (IAPS) thruster for use with LH2/LO2 propellants is described. Hydrogen was supplied at a temperature range of 22 to 33 K (40 to 60 R), and oxygen from 89 to 122 K (160 to 220 R). The thruster was designed to operate in both pulse mode and steady-state modes for vehicle attitude control, space maneuvering, and as an abort backup in the event of failure of the main propulsion system. A dual-sleeve, tri-axial injection system was designed that utilizes a primary injector/combustor where 100 percent of the oxygen and 8 percent of the hydrogen is introduced; a secondary injector/combustor where 45 percent of the hydrogen is introduced to mix with the primary combustor gases; and a boundary layer injector that uses the remaining 45 percent of the hydrogen to cool the thrust throat/nozzle design. Hot-fire evaluation of this thruster with a BLC injection distance of 2.79 cm (1.10 in.) indicated that a specific impulse value of 390 sec can be attained using a coated molybdenum thrust chamber. Pulse mode tests indicated that a chamber pressure buildup to 90 percent thrust can be achieved in a time on the order of 48 msec. Some problems were encountered in achieving ignition of each pulse during pulse trains. This was interpreted to indicate that a higher delivered spark energy level ( 100 mJ) would be required to maintain ignition reliability of the plasma torch ignition system under the extra 'cold' conditions resulting during pulsing

Orbital Stability of Planets in Binary Systems: A New Look at Old Results

About half of all known stellar systems with Sun-like stars consist of two or more stars, significantly affecting the orbital stability of any planet in these systems. This observational evidence has prompted a large array of theoretical research, including the derivation of mathematically stringent criteria for the orbital stability of planets in stellar binary systems, valid for the "coplanar circular restricted three-body problem". In the following, we use these criteria to explore the validity of results from previous theoretical studies.Comment: 3 pages, 1 figure; submitted to: Exoplanets: Detection, Formation and Dynamics, IAU Symposium 249, eds. Y.-S. Sun, S. Ferraz-Mello, and J.-L. Zhou (Cambridge: Cambridge University Press

Experimental entanglement distribution by separable states

The distribution of entanglement between macroscopically separated parties represents a crucial protocol for future quantum information networks. Surprisingly, it has been theoretically shown that two distant systems can be entangled by sending a third mediating system that is not entangled with either of them. Such a possibility seems to contradict the intuition that to distribute entanglement, the transmitted system always needs to be entangled with the sender. Here, we experimentally distribute entanglement by exchanging a subsystem and successfully prove that this subsystem is not entangled with either of the two parties. Our implementation relies on the preparation of a specific three-mode Gaussian state containing thermal noise that demolishes the entanglement in two of the three bipartite splittings. After transmission of a separable mode this noise can be removed by quantum interference. Our work demonstrates an unexpected variant of entanglement distribution and improves the understanding necessary to engineer multipartite quantum information networks.Comment: 9 pages, 6 figure

Investment Analysis of Alternative Dairy Systems under MILC

Three dairy systems, 120-cow grazing, 120-cow conventional, and 600-cow concentrated, were evaluated by internal rate of return (IRR) accounting for the Milk Income Loss Contract (MILC). With MILC, the grazing and conventional systems had higher IRRs. Without MILC, the 600-cow dairy had the highest IRR. Results were sensitive to assumptions.Concentrated feeding, conventional, grazing, internal rate of return, Livestock Production/Industries,

The Instability Transition for the Restricted 3-Body Problem. III. The Lyapunov Exponent Criterion

We establish a criterion for the stability of planetary orbits in stellar binary systems by using Lyapunov exponents and power spectra for the special case of the circular restricted 3-body problem (CR3BP). The centerpiece of our method is the concept of Lyapunov exponents, which are incorporated into the analysis of orbital stability by integrating the Jacobian of the CR3BP and orthogonalizing the tangent vectors via a well-established algorithm originally developed by Wolf et al. The criterion for orbital stability based on the Lyapunov exponents is independently verified by using power spectra. The obtained results are compared to results presented in the two previous papers of this series. It is shown that the maximum Lyapunov exponent can be used as an indicator for chaotic behaviour of planetary orbits, which is consistent with previous applications of this method, particularly studies for the Solar System. The chaotic behaviour corresponds to either orbital stability or instability, and it depends solely on the mass ratio of the binary components and the initial distance ratio of the planet relative to the stellar separation distance. Our theoretical results allow us to link the study of planetary orbital stability to chaos theory noting that there is a large array of literature on the properties and significance of Lyapunov exponents. Although our results are given for the special case of the CR3BP, we expect that it may be possible to augment the proposed Lyapunov exponent criterion to studies of planets in generalized stellar binary systems, which is strongly motivated by existing observational results as well as results expected from ongoing and future planet search missions.Comment: 10 pages, 8 figures, 3 tables; accepted by Astronomy and Astrophysic

ECONOMIC IMPACTS ON THE ILLINOIS ECONOMY OF ALTERNATIVE DAIRY PRODUCTION SYSTEMS

Dairy in Illinois has declined in farm numbers, cows, and value of dairy product. Alternative dairy systems (intensive grazing, traditional, and a concentrated feeding system) were evaluated for their potential to sustain dairy in Illinois. The economic impact of each system on the Illinois economy was evaluated using IMPLAN.Livestock Production/Industries,

PUBLIC PERCEPTIONS REGARDING GROWTH OF THE DAIRY INDUSTRY IN ILLINOIS

Community opposition to dairies has altered location decisions by milk producers. Our objective was to identify residents' perceptions towards dairy by individual and community characteristics. A mail survey of residents of dairy counties and non-dairy counties was conducted. Dairy county residents were more willing to live close to a dairy.Livestock Production/Industries,

Laser Doppler velocimeter aerial spray measurements

An experimental research program for measuring the location, spatial extent, and relative concentration of airborne spray clouds generated by agricultural aircraft is described. The measurements were conducted with a ground-based laser Doppler velocimeter. The remote sensing instrumentation, experimental tests, and the results of the flight tests are discussed. The cross section of the aerial spray cloud and the observed location, extent, and relative concentration of the airborne particulates are presented. It is feasible to use a mobile laser Doppler velocimeter to track and monitor the transport and dispersion of aerial spray generated by an agricultural aircraft

Identifying substrate proteins for GAN1 and Keap1

Abstract only availableGAN1 and Keap1 are proteins characterized by a N-terminal BTB domain and a C-terminal Kelch repeat domain. Both of these domains are protein-protein interaction domains, suggesting that these BTB-Kelch proteins form signaling complexes in cells. Previous work has suggested that BTB-Kelch proteins function as substrate adaptor proteins for Cul3-dependent E3 ubiquitin ligase complexes. The goal of this project was to identify substrate proteins of GAN1 and Keap1. This information will be particularly useful when for understanding Giant Axonal Neuropathy, a sensorimotor disease characterized by excessive accumulation of neurofilaments in neurons that contain mutated GAN1 genes. We used an affinity purification approach to identify candidate substrate proteins for GAN1 and Keap1. Recombinant GAN1 and Keap1 genes containing a C-terminal chitin binding domain (CBD) were inserted into pBabe puro vectors. These vectors were used to generate virus stocks, which were used to infect a microglial cell line, BV-2. Stable cell lines were generated using puromycin selection. A mock-infected cell line was generated in parallel. When the cell lines were confluent, the cells were lysed using a 0.1% SDS RIPA solution and chitin beads were used to precipitate the CBD-tagged proteins. Western blot analyses were performed to determine if the purification of the CBD-tagged proteins was successful. No CBD-tagged proteins were identified in our first pull-down experiment. We are currently reexamining the precipitation protocol and preparing to lysate the same set of cells.Life Sciences Undergraduate Research Opportunity Progra