Development of a KMNO\u3csub\u3e4\u3c/sub\u3e Catalyst-Infused Fuel Grain for H2O2 Hybrid Thruster Ignition Enhancement

Utah State University\u27s patented High Performance Green Hybrid Propulsion (HPGHP) technology leverages unique dielectric breakdown properties of 3D-printed acrylonitrile butadiene styrene (ABS), allowing re-start, stop, and reignition. HPGHP works most reliably using gaseous oxygen (GOX) as the oxidizer but has experienced ignition reliability and latency issues when replaced high test hydrogen peroxide (HTP), which has a significantly higher storage density. This deficiency results from HTP\u27s high decomposition energy barrier. Traditionally, inline external catalyst beds or GOX pre-lead burns are used to overcome this energy barrier to achieve ignition; however, the extra hardware required for these systems have inhibited their adoption into flight units for small satellite propulsion modules. The presented research replaces the external catalyst by diffusion-blending ABS with 1-2% potassium permanganate (KMNO4), and then 3-D printing fuel grains using the augmented feed-stock. The embedded catalyst allows for near-instantaneous decomposition as HTP enters the combustion chamber, releasing gaseous oxygen that, when combined with the arc-ignition energy, provides quick and reliable ignition. No preheat is required, and the infused fuel does not reduce the overall system performance. Drop-in design options and test results are presented for a prototype system at a1 N thrust level using 90% HTP

Estuarine Artificial Reefs to Enhance Seagrass Planting and Provide Fish Habitat

Small 25-m2 artificial reef sets were deployed 1 m deep in Choctawhatchee Bay, FL, to determine the ability of reefs to aid in the establishment of newly planted Ruppia maritima (widgeon grass) while providing habitat for estuarine fishes. Seagrass survival and coverage were examined for reef configurations and compared with control plots. Visual surveys conducted from June 1996 to May 1997 indicated that the artificial reefs had no effect on the survivorship or growth of the planted R. maritima. The artificial reefs attracted juvenile and young adult fishes and had significantly more species, higher diversity, more individuals, and greater total biomass of fishes per area than did the nonreef controls. The 22 fish species observed at the reefs were typical estuarine residents in the area. Young gray snapper, Lutjanus griseus (a recreationally and commercially important species), was abundant at the reefs. Although the artificial reefs did not increase seagrass planting success, these artificial reefs may increase the number of fishes surviving to adulthood by providing protective habitat

Interacting Hofstadter spectrum of atoms in an artificial gauge field

Motivated by experimental advances in the synthesis of gauge potentials for ultracold atoms, we consider the superfluid phase of interacting bosons on a square lattice in the presence of a magnetic field. We show that superfluid order implies spatial symmetry breaking, and predict clear signatures of many-body effects in time-of-flight measurements. By developing a Bogoliubov expansion based on the exact Hofstadter spectrum, we find the dispersion of the quasiparticle modes within the superfluid phase, and describe the consequences for Bragg spectroscopy measurements. The theory also provides an estimate of the critical interaction strength at the transition to the Mott insulator phase.Comment: 4+ pages, 2 figures; v2: published versio

The Classification and Market Pricing of the Cash Flows and Accruals on Trading Positions

We investigate whether the market prices the change in net trading assets as an operating or non-operating activity or some mixture of the two, and whether this market pricing is consistent with the (fundamental) association of the change in net trading assets with future cash flows from operations. Our investigation is motivated by the observation that – despite the classification of the cash flows on trading positions as operating under FAS 102 – trading is economically a hybrid operating/non-operating activity. Reflecting this hybrid nature, we hypothesize and find that the change in net trading assets has a less positive association with returns and future CFO than do the pure operating components of cash flows and accruals, and that it has a more positive association with returns and future CFO than do the pure non-operating components of cash flows. To the best of our knowledge, our paper is the first to propose and test hypotheses about the valuation implications of such hybrid cash flows and accruals

Using visualisation methods to analyse referral networks within community health care among patients aged 65 years and over

Community health care services are considered integral to overcoming future problems in health care. However, this sector faces its own challenges, such as how to organise services to provide coordinated care given: their physical distribution, patients using multiple services, increased patient use and differing patient needs. The aim of this work was to explore, analyse and understand patterns in community referrals for patients aged 65 years and over, and their use of multiple services through data visualisation. Working with a large community provider, these methods helped researchers and service managers to investigate questions that were otherwise difficult to answer from raw data. Each map focuses on a different characteristic of community referrals: patients reusing services, concurrent uses of different services and patterns of subsequent referrals. We apply these methods to routine patient data and discuss their implications in designing of a single point of access - a service for streamlining referrals