3,589 research outputs found

    Measurement Of Pitch-Damping Derivatives On Prithvi Model In The Nal 1.2m Tunnel

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    Pitch Damping Derivatives Were Measured On A 1/12 .5 Scale Prithvi Model Using The Forced Oscillation Technique In The NAL 1 .2m Tunnel. The Tests Were Made In The Mach Number Range Of 1 .5 To 3 .0 And At Angles Of Attack 0, 3 And 6 Deg . The Tests Were Conducted For Two Axes Of Oscillation Located At 3 .8 And 4 .05 Times The Body Diameter From The Nose. While A Majority Of The Tests Were Conducted On The 'Plus' Configuration, A Few Tests Were Also Conducted On The Into Configuration To Study The Effect Of Roll Orientation Of The Model . Both Configurations Exhibited Positive Damping Over The Range Of Test Parameters. Effects Of Angle Of Attack And Model Roll Orientation Were Found To Be Small

    Estimation of stability derivatives and dynamic stability characteristics of basic and AEW HS-748 aircraft

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    Longitudinal and lateral stability derivatives of the basic and the AEW configurations of the HS-748 aircraft have been estimated. DATCOM and ESDU Data Sheet methods were employed to estimate the complete set of derivatives of the basic aircraft. Derivatives of the AEW aircraft were obtained by a judicious use of some of the measured static wind-tunnel force and moment data in the estimation scheme. Stick-fixed and stick-free dynamic stability characteristics of the basic and the AEW aircraft were computed using the estimated stability derivatives for a range of values of the aircraft weight and C.G. location. The dynamic stability characteristics are expressed in terms of the period, damping and time-to-half amplitude of the different modes of longitudinal and lateral motions. Both the basic and the AEW aircraft are found to be stable in all modes except the spiral mode, which exhibits a mild divergence. Damping of the lateral oscillatory mode with rudder-free, although positive, is rather low for both the basic and the AEW configurations. In general, installation of rotodome reduces the effectiveness of horizontal and vertical stabilizers and also the control effectiveness of the elevator and rudder, but it does not cause any major qualitative changes In the dynamic stability characteristics of the aircraft

    Smartphone microendoscopy for high resolution fluorescence imaging

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    High resolution optical endoscopes are increasingly used in diagnosis of various medical conditions of internal organs, such as the gastrointestinal tracts, but they are too expensive for use in resource-poor settings. On the other hand, smartphones with high resolution cameras and Internet access have become more affordable, enabling them to diffuse into most rural areas and developing countries in the past decade. In this letter we describe a smartphone microendoscope that can take fluorescence images with a spatial resolution of 3.1 {\mu}m. Images collected from ex vivo, in vitro and in vivo samples using the device are also presented. The compact and cost-effective smartphone microendoscope may be envisaged as a powerful tool for detecting pre-cancerous lesions of internal organs in low and middle income countries.Comment: 4 pages, 4 figure

    Nucleophilic substitutions on 3-chloro-4- fluoronitrobenzene

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    Nucleophilic substitutions on 3-chloro-4- fluoronitrobenzene 5 with piperazines occur on the fluorine rather than on the chlorine atom as reported, to yield 3-chloro-4-piperazinylnitrobenzenes 8 and 9

    Financial Liberalization, Bank Restructuring and the Options for Client-Owned Intermediation: Two African Experiences in Rudimentary Financial Markets

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    The impact of structural adjustment programs in Sub-Saharan Africa have now generated a decade long history. The impact of deregulation and privatization on the restructuring of banks and their performance is little studied, along with its implications for servicing constituencies rationed out of the liberalized banks portfolios. This paper reviews this experience of bank restructuring and the implications for the post-liberalization supply of financial services in The Gambia and Mozambique. Lessons for other African countries are highlighted for review
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