122 research outputs found

    Development and flight test results of an autothrottle control system at Mach 3 cruise

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    Flight test results obtained with the original Mach hold autopilot designed the YF-12C airplane which uses elevator control and a newly developed Mach hold system having an autothrottle integrated with an altitude hold autopilot system are presented. The autothrottle tests demonstrate good speed control at high Mach numbers and high altitudes while simultaneously maintaining control over altitude and good ride qualities. The autothrottle system was designed to control either Mach number or knots equivalent airspeed (KEAS). Excellent control of Mach number or KEAS was obtained with the autothrottle system when combined with altitude hold. Ride qualities were significantly better than with the conventional Mach hold system

    Eigensystem synthesis for active flutter suppression on an oblique-wing aircraft

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    The application of the eigensystem synthesis technique to place the closed-loop eigenvalues and shape the closed-loop eigenvectors has not been practical for active flutter suppression, primarily because of the availability of only one control surface (aileron) for flutter suppression. The oblique-wing aircraft, because of its configuration, provides two independent surfaces (left and right ailerons), making the application of eigensystem synthesis practical. This paper presents the application of eigensystem synthesis using output feedback for the design of an active flutter suppression system for an oblique-wing aircraft. The results obtained are compared with those obtained by linear quadratic Gaussian techniques

    Aeroelastic control of oblique-wing aircraft

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    The U.S. Navy and NASA are currently involved in the design and development of an unsymmetric-skew-wing aircraft capable of 65 deg wing sweep and flight at Mach 1.6. A generic skew-wing aircraft model was developed for 45 deg wing skew at a flight condition of Mach 0.70 and 3048 m altitude. At this flight condition the aircraft has a wing flutter mode. An active implementable control law was developed using the linear quadratic Gaussian design technique. A method of modal residualization was used to reduce the order of the controller used for flutter suppression

    Effect of Distillers Grains Plus Solubles and Monensin Supplementation on Grazing Steers

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    Yearling steers rotationally grazing smooth bromegrass were individually supplemented monensin at 0 or 200 mg with modified distillers grains plus solubles (MDGS) at .05, 0.4, 0.6, and 0.8% BW. Cannulated steers continuously grazing smooth bromegrass were assigned randomly to one of two treatments: 0.4% BW MDGS supplementation with 0 or 200 mg monensin. Monensin did not affect ADG of steers supplemented MDGS ≄ 0.4% BW. Steers supplemented with monensin had a decreasein estimated average forage intakefrom 16.16 lb to 14.75 lb/OM daily

    Effects of Syngenta Enogen Feed Corn containing an α-amylase trait on finishing cattle performance and carcass characteristics

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    Two experiments evaluated the effects of feeding a new corn hybrid, containing an α-amylase enzyme trait, Syngenta Enogen Feed Corn (SYT-EFC), on feedlot performance and carcass characteristics at two locations. Experiment 1 utilized 300 calffed steers (298.5 ± 16.3 kg of BW) at the University of Nebraska–Lincoln Eastern Nebraska Research and Extension Center Mead, NE. Treatments were designed as a 2 × 2 + 1– factorial arrangement with factors consisting of 1) corn type (SYT-EFC or conventional [CON]) and 2) byproduct type (with or without Sweet Bran [SB]), or a BLEND of STY-EFC and CON without SB. In Exp. 2, 240 crossbred, calf-fed steers (287.6 ± 15.4 kg of BW) were utilized at the University of Nebraska–Lincoln Panhandle Research and Extension Center near Scottsbluff, NE. Steers were fed SYT-EFC, CON, BLEND, or CON with a commercial α-amylase enzyme supplement (CON-E). In Exp. 1, there was an interaction for ADG (P = 0.05) and G:F (P = 0.02). Steers fed SYT-EFC with SB had greater ADG and G:F than CON; however, in diets without SB, SYT-EFC and CON were not different resulting in a 10.1% change in G:F when steers were fed SYT-EFC in SB compared with CON and only 1.6% change between SYT-EFC and CON without SB. Energy values, based on performance data, resulted in a 6.5% and 8.3% change in NEm and NEg, respectively, for steers fed SYT-EFC and CON with SB and 1.6% change for both NEm and NEg for steers fed SYT-EFC and CON without SB. For the main effect of corn trait, steers fed SYT-EFC had greater marbling scores, fat depth, and calculated yield grade compared with CON (P ≀ 0.03). In diets without SB, there was no difference between SYT-EFC, CON, or BLEND for DMI, final BW, ADG, G:F, NEm, or NEg (P ≄ 0.35). In Exp. 2, cattle fed SYT-EFC, BLEND, or CON-E had greater final BW, ADG, and G:F than cattle fed CON (P ≀ 0.03). On average, NEm and NEg were 4.9% and 7.0% greater, respectively, for steers fed amylase enzyme treatments compared with CON (P ≀ 0.01). Hot carcass weights were greater in steers fed α-amylase treatments compared with CON (P \u3c 0.01). Feeding Syngenta Enogen Feed Corn, which contains an α-amylase enzyme trait, at both locations improved feed efficiency in finishing cattle diets containing WDGS or SB

    New hydroxylated metabolites of 4-monochlorobiphenyl in whole poplar plants

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    Two new monohydroxy metabolites of 4-monochlorobiphenyl (CB3) were positively identified using three newly synthesized monohydroxy compounds of CB3: 2-hydroxy-4-chlorobiphenyl (2OH-CB3), 3-hydroxy-4-chlorobiphenyl (3OH-CB3) and 4-hydroxy-3-chlorobiphenyl (4OH-CB2). New metabolites of CB3, including 2OH-CB3 and 3OH-CB3, were confirmed in whole poplars (Populus deltoides × nigra, DN34), a model plant in the application of phytoremediation. Furthermore, the concentrations and masses of 2OH-CB3 and 3OH-CB3 formed in various tissues of whole poplar plants and controls were measured. Results showed that 2OH-CB3 was the major product in these two OH-CB3s with chlorine and hydroxyl moieties in the same phenyl ring of CB3. Masses of 2OH-CB3 and 3OH-CB3 in tissues of whole poplar plants were much higher than those in the hydroponic solution, strongly indicating that the poplar plant itself metabolizes CB3 to both 2OH-CB3 and 3OH-CB3. The total yield of 2OH-CB3 and 3OH-CB3, with chlorine and hydroxyl in the same phenyl ring of CB3, was less than that of three previously found OH-CB3s with chlorine and hydroxyl in the opposite phenyl rings of CB3 (2'OH-CB3, 3'OH-CB3, and 4'OH-CB3). Finally, these two newly detected OH-CB3s from CB3 in this work also suggests that the metabolic pathway was via epoxide intermediates. These five OH-CB3s clearly showed the complete metabolism profile from CB3 to monohydroxylated CB3. More importantly, it's the first report and confirmation of 2OH-CB3 and 3OH-CB3 (new metabolites of CB3) in a living organism

    Cross-tolerance to abiotic stresses in halophytes: Application for phytoremediation of organic pollutants

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    International audienceHalopytes are plants able to tolerate high salt concentrations but no clear definition was retained for them. In literature, there are more studies that showed salt-enhanced tolerance to other abiotic stresses compared to investigations that found enhanced salt tolerance by other abiotic stresses in halophytes. The phenomenon by which a plant resistance to a stress induces resistance to another is referred to as cross-tolerance. In this work, we reviewed cross-tolerance in halophytes at the physiological, biochemical, and molecular levels. A special attention was accorded to the cross-tolerance between salinity and organic pollutants that could allow halophytes a higher potential of xenobiotic phytoremediation in comparison with glycophytes

    Scaling Behavior of Human Locomotor Activity Amplitude: Association with Bipolar Disorder

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    Scale invariance is a feature of complex biological systems, and abnormality of multi-scale behaviour may serve as an indicator of pathology. The hypothalamic suprachiasmatic nucleus (SCN) is a major node in central neural networks responsible for regulating multi-scale behaviour in measures of human locomotor activity. SCN also is implicated in the pathophysiology of bipolar disorder (BD) or manic-depressive illness, a severe, episodic disorder of mood, cognition and behaviour. Here, we investigated scaling behaviour in actigraphically recorded human motility data for potential indicators of BD, particularly its manic phase. A proposed index of scaling behaviour (Vulnerability Index [VI]) derived from such data distinguished between: [i] healthy subjects at high versus low risk of mood disorders; [ii] currently clinically stable BD patients versus matched controls; and [iii] among clinical states in BD patients
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