11,889 research outputs found
Switched Capacitor Voltage Converter
This project supports IoT development by reducing the power con- sumption and physical footprint of voltage converters. Our switched- capacitor IC design steps down an input of 1:0 - 1:4 V to 0:6 V for a decade of load current from 5 - 50A
Stochastic model of the NASA/MSFC ground facility for large space structures with uncertain parameters: The maximum entropy approach
A stochastic control model of the NASA/MSFC Ground Facility for Large Space Structures (LSS) control verification through Maximum Entropy (ME) principle adopted in Hyland's method was presented. Using ORACLS, a computer program was implemented for this purpose. Four models were then tested and the results presented
A method for linearizing a nonlinear system with six state variables and three control variables
A nonlinear system governed by x = f(x,u) with six state variables and three control variables is considered in this project. A set of transformations from (x,u) - space to (z,v) - space is defined such that the linear tangent model is independent of the operating point in the z-space. Therefore, it is possible to design a control law satisfying all operating points in the transformed space. An algorithm to construct the above transformations and to obtain the associated linearized system is described in this report. This method is applied to a rigid body using pole placement for the control law. Results are verified by numerical simulation. Closed loop poles in x-space using traditional local linearization are compared with those pole placements in the z-space
Discovery of new low-excitation planetary nebulae
We report a multi-wavelength study of four new planetary nebula (PN)
candidates selected from the INT/WFC Photometric Ha Survey of the Northern
Galactic Plane (IPHAS) and Deep Sky Hunter (DSH) catalogues. We present
mid-resolution optical spectra of these PNs. The PN status of our sample was
confirmed by optical narrow-band images and mid-resolution spectra. Based on
the locations of these objects in the log (Ha/[N II]) versus log (Ha/[S II])
diagnostic diagram, we conclude that these sources are evolved lowexcitation
PNs. The optical and infrared appearances of these newly discovered PNs are
discussed. Three of the new nebulae studied here are detected in infrared and
have low infrared-to-radio flux ratios, probably suggesting that they are
evolved. Furthermore, we derive the dynamical ages and distances of these
nebulae and study the spectral energy distribution for one of them with
extensive infrared archival data.Comment: 11 pages, 9 figures, 6 tables, accepted for publication on Astronomy
& Astrophysic
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