983 research outputs found

    Characteristics of hingeless rotors with hub moment feedback controls including experimental rotor frequency response, Volume 1

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    Wind tunnel tests to determine the dynamic characteristics of hingeless rotors with hub moment feedback controls and to acquire experimental hingeless rotor transfer functions are discussed. Rotor transfer functions were calculated from data acquired during open loop frequency response tests. The transfer functions are linear and present the rotor longitudinal and lateral frequency responses to collective pitch, longitudinal cyclic pitch, and lateral cyclic pitch. The theoretical analysis was based on the rigid blade flapping model coupled with appropriate control system and cyclic pitch actuator equations of motion

    Research program to determine rotor response characteristics at high advance ratios Final report

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    Stability and response characteristics of directly controlled rigid rotors at high advance ratios and correlation of mathematical model with wind tunnel test dat

    Experimental Hingeless Rotor Characteristics at Full Scale First Flap Mode Frequencies (including Rotor Frequency Response to Shaft Oscillations), Phase 3

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    The completion of the High Advance Ratio Research Program is reported. The primary objectives of the program were to experimentally determine the rotor frequency response to shaft pitching and rolling oscillations and to acquire steady response and frequency response data at high advance ratios for hingeless rotors with typical, full-scale, first flap mode natural frequencies. Secondary objectives of the program included the further evaluation of both the hub moment feedback control system and the simplified rigid blade flapping theory with respect to shaft oscillations. The bulk of the text is devoted to the presentation and examination of representative experimental results. All the analyzed test data are documented in tabular and/or graphical formats

    Methanol adsorption by amorphous silica alumina in the critical temperature range

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    The methanol adsorption capacity of an amorphous silica-alumina was measured using an equilibrium technique. The experimental temperature range was of 140 to 260°C and the pure methanol pressure range was 0.1 to 1.2 MPa. A multilayer adsorption was found, also for temperatures above the critical temperature of the adsorbate. Based on the Jovanovic adsorption model, the mean residence times of the adsorbed molecules were calculated. Surprisingly, the heat of adsorption was found to be independent of the temperature in the multilayer adsorption range

    Does antenatal micronutrient supplementation improve children’s cognitive function? Evidence from the follow-up of a double-blind randomised controlled trial in Nepal

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    INTRODUCTION: Multiple Micronutrient (MMN) supplementation during pregnancy can decrease the proportion of infants born low birth weight and small for gestational age. Supplementation could also enhance children’s cognitive function by improving access to key nutrients during fetal brain development and increasing birth weight, especially in areas where undernutrition is common. We tested the hypothesis that children whose mothers received MMN supplementation during pregnancy would have higher intelligence in early adolescence compared with those receiving Iron and Folic Acid (IFA) only. METHODS: We followed up children in Nepal, whose mothers took part in a double-blind Randomised Controlled Trial (RCT) that compared the effects on birth weight and gestational duration of antenatal MMN versus IFA supplementation. We assessed children’s Full Scale Intelligence Quotient (FSIQ) using the Universal Non-verbal Intelligence Test (UNIT), and their executive function using the counting Stroop test. The parent trial was registered as ISRCTN88625934. RESULTS: We identified 813 (76%) of the 1069 children whose mothers took part in the parent trial. We found no differences in FSIQ at 12 years between MMN and IFA groups (absolute difference in means (diff): 1.25, 95% CI −0.57 to 3.06). Similarly, there were no differences in mean UNIT memory (diff: 1.41, 95% CI −0.48 to 3.30), reasoning (diff: 1.17, 95% CI −0.72 to 3.06), symbolic (diff: 0.97, 95% CI −0.67 to 2.60) or non-symbolic quotients (diff: 1.39, 95% CI −0.60 to 3.38). CONCLUSION: Our follow-up of a double-blind RCT in Nepal found no evidence of benefit from antenatal MMN compared with IFA for children’s overall intelligence and executive function at 12 years

    Induced Anticlinic Ordering and Nanophase Segregation of Bow-Shaped Molecules in a Smectic Solvent

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    Recent experiments indicate that doping low concentrations of bent-core molecules into calamitic smectic solvents can induce anticlinic and biaxial smectic phases. We have carried out Monte Carlo (MC) simulations of mixtures of rodlike molecules (hard spherocylinders with length/breadth ratio Lrod/D=5L_{\rm rod}/D = 5) and bow- or banana-shaped molecules (hard spherocylinder dimers with length/breadth ratio Lban/D=5L_{ban}/D = 5 or 2.5 and opening angle ψ\psi) to probe the molecular-scale organization and phase behavior of rod/banana mixtures. We find that a low concentration (3%) of Lban/D=5L_{ban}/D = 5 dimers induces anticlinic (SmCA_A) ordering in an untilted smectic (SmA) phase for 100ψ<150100^\circ \le \psi < 150^\circ. For smaller ψ\psi, half of each bow-shaped molecule is nanophase segregated between smectic layers, and the smectic layers are untilted. For Lban/D=2.5L_{ban}/D = 2.5, no tilted phases are induced. However, with decreasing ψ\psi we observe a sharp transition from {\sl intralamellar} nanophase segregation (bow-shaped molecules segregated within smectic layers) to {\sl interlamellar} nanophase segregation (bow-shaped molecules concentrated between smectic layers) near ψ=130\psi = 130^\circ. These results demonstrate that purely entropic effects can lead to surprisingly complex behavior in rod/banana mixtures.Comment: 5 pages Revtex, 7 postscript figure

    Cryptic species within the wheat curl mite Aceria tosichella (Keifer) (Acari: Eriophyoidea), revealed by mitochondrial, nuclear and morphometric data.

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    Transkingdom Networks: A Systems Biology Approach to Identify Causal Members of Host-Microbiota Interactions

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    Improvements in sequencing technologies and reduced experimental costs have resulted in a vast number of studies generating high-throughput data. Although the number of methods to analyze these "omics" data has also increased, computational complexity and lack of documentation hinder researchers from analyzing their high-throughput data to its true potential. In this chapter we detail our data-driven, transkingdom network (TransNet) analysis protocol to integrate and interrogate multi-omics data. This systems biology approach has allowed us to successfully identify important causal relationships between different taxonomic kingdoms (e.g. mammals and microbes) using diverse types of data
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