Voltage regulator dissipates minimal power and functions as a voltage divider

Regulator requires minimum amount of power for voltage division and it is not required continuously. The only power loss, except for regulating purposes, is that needed to provide for imbalances in load current requirements. For balanced loads, only leakage current flows through regulating transistors

Building From Within: Designing a Values-Based Cultural Template

Lifelong education and prolific writer Joseph Hester, together with businessman and philosopher H. Darrell Young, combine their years of knowledge and experience to introduce the reader to a cultural business plan designed for rebuilding businesses and organizations on a values foundation

Self-organizing search lists using probabilistic back-pointers

A class of algorithms is given for maintaining self-organizing sequential search lists, where the only permutation applied is to move the accessed record of each search some distance towards the front of the list. During searches, these algorithms retain a back-pointer to a previously probed record in order to determine the destination of the accessed record's eventual move. The back-pointer does not traverse the list, but rather it is advanced occationally to point to the record just probed by the search algorithm. This avoids the cost of a second traversal through a significant portion of the list, which may be a significant savings when each record access may require a new page to be brought into primary memory. Probabilistic functions for deciding when to advance the pointer are presented and analyzed. These functions demonstrate average case complexities of measures such as asymptotic cost and convergence similar to some of the more common list update algorithms in the literature. In cases where the accessed record is moved forward a distance proportional to the distance to the front of the list, the use of these functions may save up to 50% of the time required for permuting the list

Generation of optimal binary split trees

A binary split tree is a search structure combining features of heaps and binary search trees. Building an optimal binary split tree was originally conjectured to be intractable due to difficulties in applying dynamic programming techniques to the problem. However, two algorithms have recently been published which purportedly generate optimal trees in O(n^5) time, for records with distinct access probabilities. An extension allowing non-distinct access probabilities required exponential time. These algorithms consider a range of values when only a single value is possible, and may select an infeasible value which leads to an incorrect result. A dynamic programming method for determining the correct value is given, resulting in an algorithm which builds an optimal binary split tree in O(n^5) time for non-distinct access probabilities and Θ(n^4) time for distinct access probabilities

Optimal Pebbling in Products of Graphs

We prove a generalization of Graham's Conjecture for optimal pebbling with arbitrary sets of target distributions. We provide bounds on optimal pebbling numbers of products of complete graphs and explicitly find optimal $t$-pebbling numbers for specific such products. We obtain bounds on optimal pebbling numbers of powers of the cycle $C_5$. Finally, we present explicit distributions which provide asymptotic bounds on optimal pebbling numbers of hypercubes.Comment: 28 pages, 1 figur

Break up of returning plasma after the 7 June 2011 filament eruption by Rayleigh-Taylor instabilities

A prominence eruption on 7 June 2011 produced spectacular curtains of plasma falling through the lower corona. At the solar surface they created an incredible display of extreme ultraviolet brightenings. The aim is to identify and analyze some of the local instabilities which produce structure in the falling plasma. The structures were investigated using SDO/AIA 171A and 193A images in which the falling plasma appeared dark against the bright coronal emission. Several instances of the Rayleigh-Taylor instability were investigated. In two cases the Alfven velocity associated with the dense plasma could be estimated from the separation of the Rayleigh-Taylor fingers. A second type of feature, which has the appearance of self-similar branching horns, is also discussed.Comment: 6 pages, 7 figures, submitted A&A. Movies are at http://www.mps.mpg.de/data/outgoing/innes/arcs_movie.avi and http://www.mps.mpg.de/data/outgoing/innes/horns_movie.av

In Situ Resonance Raman Spectroscopic Investigation of a Polypyrrole Modified Gold Electrode

Resonance Raman spectroseopy has been used in situ to study polypyrrole (PP) modified gold electrodes. Broad bands observed in the 1100-1600 cm" region of spectra of both oxidized (electrically conducting) PP+ and the reduced insulating ppo forms have been interpreted in terms of the highly disordered structure of polypyrrole. Strong correlations between the band positions of polypyrrole and 2,5-dialkyl substituted pyrroles are noted and tentative assignments for polypyrrole bands are made from those of the 2,5-dialkyl pyrroles. The wave numbers of bands at ea. 920-930, 1250-\u27:1260and 1540-1550 cm? in the Raman spectra of polypyrrole showa strong correlation with bands observed in the Raman spectra of cis-polyacetylene. This suggests that the conjugated carbon chain backbones in polypyrrole and cis-polyacetylene are similar

Coarse level Newton-Krylov acceleration of sub-iterations in partitioned fluid-structure interaction

Computational fluid-structure interaction is commonly performed using a partitioned approach. For strongly coupled problems sub-iterations are required, increasing computational time as flow and structure have to be resolved multiple times every time step. Reductions in computing times can be achieved by e.g. improving the convergence of the sub-iteration technique and/or performing sub-iterations on a coarse level, but also by improving the iterative solver used in the flow solver. In this paper we investigate the combination of a multilevel acceleration technique for sub-iterations which employs a Newton-Krylov solver on the coarse level to obtain high convergence for the correction term and a multigrid solver which performs only a limited amount of iterations on the fine level to reduce memory and computing requirements. For switching between a coarse grid correction and fine grid solve, an automated coarse grid ACG(r) selection algorithm is proposed. The algorithm is applied to an academic, two dimensional test case with incompressible flow. Compared to sub-iterating with a (memory intensive) JFNK algorithm on the fine mesh, the hybrid algorithm already requires 10% less computing time. When compared to sub-iterating with multigrid, the performance increase for the hybrid scheme is a factor 3

In Situ Resonance Raman Spectroscopic Investigation of a Polypyrrole Modified Gold Electrode

Resonance Raman spectroseopy has been used in situ to study polypyrrole (PP) modified gold electrodes. Broad bands observed in the 1100-1600 cm" region of spectra of both oxidized (electrically conducting) PP+ and the reduced insulating ppo forms have been interpreted in terms of the highly disordered structure of polypyrrole. Strong correlations between the band positions of polypyrrole and 2,5-dialkyl substituted pyrroles are noted and tentative assignments for polypyrrole bands are made from those of the 2,5-dialkyl pyrroles. The wave numbers of bands at ea. 920-930, 1250-\u27:1260and 1540-1550 cm? in the Raman spectra of polypyrrole showa strong correlation with bands observed in the Raman spectra of cis-polyacetylene. This suggests that the conjugated carbon chain backbones in polypyrrole and cis-polyacetylene are similar