Summary of recent design studies of advanced acoustic-composite nacelles

The results are summarized of recent NASA-sponsored studies of advanced acoustic-composite nacelles. Conceptual nacelle designs for current wide-bodied transports and for advanced technology transports, intended for operational use in the mid-1980's, were studied by Lockheed-California Company and the Douglas Aircraft Company. These studies were conducted with the objective of achieving significant reductions in community noise and/or fuel consumption with minimum penalties in airplane weights, cost, and operating expense. The results indicate that the use of advanced composite materials offer significant potential weight and cost savings and result in reduced fuel consumption and noise when applied to nacelles. The most promising concept for realizing all of these benefits was a long duct, mixed flow acoustic composite nacelle with advanced acoustic liners

Hepatitis C Diagnoses in an American Indian Primary Care Population

BACKGROUND: Despite large disparities in the burden of chronic liver disease, data on hepatitis C virus (HCV) infection among American Indians (AIs) are lacking. We reviewed hepatitis C diagnoses in 35,712 AI/AN primary care patients. MAIN FINDINGS: At least one HCV-associated ICD-9 code was recorded in 251 (1%) patients between October 1, 2001 and September 30, 2003. An HCV enzyme-linked immunoassay (HCVEIA) was sent in 209 (83.0%); 206/209 (99%) were positive. Confirmatory testing was performed in 144/206 (70%) HCV-EIA positive patients; HCV infection was confirmed in 144 (100%). In the 90/144 (63%) charts with risk factor documentation, injection drug use was the most common risk factor (61/90, 68%). Deficiencies were present in hepatitis B and HIV testing, and hepatitis A and B vaccination. PRINCIPAL CONCLUSIONS: Improvements in laboratory workup of HCV and co-infections, risk factor ascertainment and documentation, and adult vaccination are needed to address HCV effectively in this population

Properties of non-stoichiometric metallic carbides final report

Nonstoichiometric transition metal carbide propertie

An Internet-Based Tool for Weather Risk Management

This paper introduces a web-based computer program designed to evaluate weather risk man-agement and weather insurance in the United States. The paper outlines the economics of weather risk in terms of agricultural production and household well-being; defines weather risk in terms of intensity, duration, and frequency; and illustrates the computer program use by comparing heat and precipitation risks at Ardmore, Oklahoma, and Ithaca, New York.weather insurance, heat insurance, precipitation insurance, crop insurance, weather derivatives, Risk and Uncertainty,

Vulnerability of LTE to Hostile Interference

LTE is well on its way to becoming the primary cellular standard, due to its performance and low cost. Over the next decade we will become dependent on LTE, which is why we must ensure it is secure and available when we need it. Unfortunately, like any wireless technology, disruption through radio jamming is possible. This paper investigates the extent to which LTE is vulnerable to intentional jamming, by analyzing the components of the LTE downlink and uplink signals. The LTE physical layer consists of several physical channels and signals, most of which are vital to the operation of the link. By taking into account the density of these physical channels and signals with respect to the entire frame, as well as the modulation and coding schemes involved, we come up with a series of vulnerability metrics in the form of jammer to signal ratios. The ``weakest links'' of the LTE signals are then identified, and used to establish the overall vulnerability of LTE to hostile interference.Comment: 4 pages, see below for citation. M. Lichtman, J. Reed, M. Norton, T. Clancy, "Vulnerability of LTE to Hostile Interference'', IEEE Global Conference on Signal and Information Processing (GlobalSIP), Dec 201

Economic Significance of Specific Export Promotion on Poverty Reduction and Inter- Industry Growth of Ethiopia

Micro simulated general equilibrium approach was used to analyze the economic significance of the current export promotion policy of Ethiopia. Simulation results, in general, indicated little achievements of economic growth and poverty reduction under selective export promotion. In this policy approach, only rural households were able to acquire higher income and lower poverty incidence. These achievements however were transmitted to small and big urban households when export promotion was assumed to be implemented across the board of all agricultural activities. Significant economic and inter-industrial growths were attained when the coffee industry was given equal policy treatments like other export agricultureSelective export promotion policy, computable general equilibrium, poverty reduction, foreign direct investment, Land Economics/Use, Resource /Energy Economics and Policy,

EFFECTS OF ALTERNATIVE IRRIGATION ALLOCATIONS ON WATER USE, NET RETURNS, AND MARGINAL USER COSTS

Resource /Energy Economics and Policy,

Magnetic Cataclysmic Variable Accretion Flows

We have used a magnetic accretion model to investigate the accretion flows of magnetic cataclysmic variables (mCVs) throughout a range of parameter space. The results of our numerical simulations demonstrate that broadly four types of flow are possible: discs, streams, rings and propellers. We show that the equilibrium spin periods in asynchronous mCVs, for a given orbital period and magnetic moment, occur where the flow changes from a type characterised by spin-up (i.e. disc or stream) to one characterised by spin-down (i.e. propeller or ring). 'Triple points' occur in the plane of spin-to-orbital period ratio versus magnetic moment, at which stream-disc-propeller flows or stream-ring-propeller flows can co-exist. The first of these is identified as corresponding to when the corotation radius is equal to the circularisation radius, and the second as where the corotation radius is equal to the distance from white dwarf to the L1 point. If mCVs are accreting at their equilibrium spin rates, then for a mass ratio of 0.5, those with Pspin/Porb < 0.1 will be disc-like, those with 0.1 < Pspin/Porb < 0.5 will be stream-like, and those with Pspin/Porb ~ 0.5 will be ring-like. In each case, some material is also lost from the binary in order to maintain angular momentum balance. The spin to orbital period ratio at which the systems transition between these flow types decreases as the mass ratio of the stellar components increases, and vice versa

Weather Index Insurance and the Pricing of Spatial Basis Risk

Agricultural Finance,