2,457 research outputs found
Shifting Gears: State Innovation to Advance Workers and the Economy in the Midwest
Outlines five states' policy actions to expand access to postsecondary credentials and careers and innovations implemented through Joyce's initiative, including combining basic skills content with workforce readiness, support services, and specialization
The prediction of transonic loading advancing helicopter rotors
Two different schemes are presented for including the effect of rotor wakes on the finite-difference prediction of rotor loads. The first formulation includes wake effects by means of a blade-surface inflow specification. This approach is sufficiently simple to permit coupling of a full-potential finite-difference rotor code to a comprehensive integral model for the rotor wake and blade motion. The coupling involves a transfer of appropriate loads and inflow data between the two computer codes. Results are compared with experimental data for two advancing rotor cases. The second rotor wake modeling scheme in this paper is a split potential formulation for computing unsteady blade-vortex interactions. Discrete vortex fields are introduced into a three-dimensional, conservative, full-potential rotor code. Computer predictions are compared with two experimental blade-vortex interaction cases
States of Change
States of Change documents efforts by state policymakers and local practitioners to devise useful approaches to helping low-income job seekers stay employed and begin advancing. It draws, in part, from our experiences working on these issues since 1997 with five states -- Washington, Oregon, Colorado, Oklahoma and Florida -- as well as on examples and lessons in several other states. In general, states are trying a number of retention strategies, but few have been tested. Therefore, we expect that many strategies discussed will soon be modified or replaced with new approaches. We hope that States of Change encourages this process of testing and innovation by providing a sense of what is being tried and learned around the country, and what challenges remain
Connectivity and Irreducibility of Algebraic Varieties of Finite Unit Norm Tight Frames
In this paper, we settle a long-standing problem on the connectivity of
spaces of finite unit norm tight frames (FUNTFs), essentially affirming a
conjecture first appearing in [Dykema and Strawn, 2003]. Our central technique
involves continuous liftings of paths from the polytope of eigensteps to spaces
of FUNTFs. After demonstrating this connectivity result, we refine our analysis
to show that the set of nonsingular points on these spaces is also connected,
and we use this result to show that spaces of FUNTFs are irreducible in the
algebro-geometric sense, and also that generic FUNTFs are full spark.Comment: 33 pages, 4 figure
Improving alternative fuel efficiency with water injection
Alternative fuel internal combustion engines (ICEs) have been increasing in popularity as the harmful effects of pollution and the need for a sustainable energy source are becoming more apparent. Two alternative fuels, E85 and hydrogen gas, are considered in this study. These fuels are renewable and have less emissions than traditional fuels, but there are many inherent disadvantages to their use. Water injection could alleviate some of the issues that plague these fuels. To test this, a Briggs and Stratton Baja engine was used, with and without water injection. Gasoline with water injection showed better performance than without: the power with water injection was 10.26 hp while the power without injection was 10.35 hp. Further tests with E85 were planned, but due to equipment malfunctions, these tests could not be performed. Instead of experimental test results, theoretical curves for E85 were found. E85 had a performance that was 80% of gasoline’s. Adding water injection increased E85’s performance to 92% of gasoline’s performance. These results show that water injection is capable of increasing engine performance. It is possible that the benefits of water injection could also apply to hydrogen fuel. Implementation of water injection in a hydrogen fuel ICE would alleviate some of the issues that are inherent in these systems, allowing for improvements in design and operation. Water injection could increase the viability of alternative fuel ICEs
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