8,660 research outputs found
Wind tunnel tests on a tail-less swept wing span-distributed cargo aircraft configuration
The configuration consisted of a 30 deg -swept, untapered, untwisted wing utilizing a low-moment cambered airfoil of 20 percent streamwise thickness designed for low wave drag at M = 0.6, C sub L = 0.4. The tests covered a range of Mach numbers 0.3 to 0.725 and chord Reynolds number 1,100,000 to 2,040,000, angles of attack up to model buffet and sideslip angles + or - 4 deg. Configuration build up, wing pod filleting, airfoil modification and trailing edge control deflection effects were briefly investigated. Three wing tip vertical tail designs were also tested. Wing body filleting and a simple airfoil modification both produced increments to maximum lift/drag ratio. Addition of pods eliminated pitch instability of the basic wing. While the magnitude of these benefits probably was Reynolds number sensitive, they underline the potential for improving the aerodynamics of the present configuration. The cruise parameter (product of Mach number and lift/drag ratio) attained a maximum close to the airfoil design point. The configuration was found to be positively stable with normal control effectiveness about all three axes in the Mach number and C sub L range of interest
Teacher and Administrator Perceptions of a Balanced School Calendar and its Effects on Students in Poverty
The creation of this study came out of a need to increase student achievement and support services for students living in poverty in the selected school district in Missouri. Due to the large amount of academic regression over the long summer break and the lack of consistent support services for students in poverty, a Balanced School Calendar (BSC) was investigated. The researchers conducted surveys and interviews to assess the level of support from parents, teachers, and administrators to see if a BSC school choice program would be a viable option for implementation at a K-5 elementary school in the selected school district in Missouri. The findings of this study show that that there is a significant difference in the perceptions of administrators and teachers in the concept of a BSC especially in the areas of regression, discipline, support services, teacher stress, relationship building, and willingness to teach in a BSC school
Alteration of Symptom Expression In the Cereal Rusts
Cheyenne wheat was treated with varying concentrations of maleic hydrazide and indoleacetic acid in separate and combined applications. Lower concentrations of maleic hydrazide have an inhibitory effect upon germination of wheat seeds and vegetative growth but a stimulatory effect upon uredial pustule development of the leaf rust fungus (Puccinia recondita Rob. ex Desm.). Higher concentrations of maleic hydrazide further inhibit germination and vegetative growth of the host plant, but also inhibit development of the leaf rust fungus. Indoleacetic acid has a stimulatory effect on vegetative growth of the wheat plant at rather low concentrations. At the same time it tends to suppress the inhibitory action of heavier concentrations of maleic hydrazide on the leaf rust fungus when the two are applied in combined treatments
NP-hardness of decoding quantum error-correction codes
Though the theory of quantum error correction is intimately related to the
classical coding theory, in particular, one can construct quantum error
correction codes (QECCs) from classical codes with the dual containing
property, this does not necessarily imply that the computational complexity of
decoding QECCs is the same as their classical counterparts. Instead, decoding
QECCs can be very much different from decoding classical codes due to the
degeneracy property. Intuitively, one expect degeneracy would simplify the
decoding since two different errors might not and need not be distinguished in
order to correct them. However, we show that general quantum decoding problem
is NP-hard regardless of the quantum codes being degenerate or non-degenerate.
This finding implies that no considerably fast decoding algorithm exists for
the general quantum decoding problems, and suggests the existence of a quantum
cryptosystem based on the hardness of decoding QECCs.Comment: 5 pages, no figure. Final version for publicatio
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Contains reports on two research projects.Lincoln Laboratory (Purchase Order DDL-B187)Department of the ArmyDepartment of the NavyDepartment of the Air Force under Contract AF19(122)-45
Winners and Losers: Formula versus Competitive Funding of Agricultural Research
Research and Development/Tech Change/Emerging Technologies, O3, O4, Q16,
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