Circuit controls transients in SCR inverters

Elimination of starting difficulties in SCR inverters is accomplished by the addition of two taps of the output winding of the inverter. On starting or under transient loads, the two additional taps deliver power through diodes without requiring quenching of SCR currents in excess of normal starting load

Power conditioning - inversion, conversion, and regulation

Switching element requirements for spacecraft electric power conversion, inversion, and regulatio

Distance to U Pegasi by the DDE Algorithm

A distance is found for the W UMa type binary U Pegasi, with a newly modified version of the Wilson-Devinney program (W-D) that makes use of the direct distance estimation (DDE) algorithm. The reported distance of d = 123.6pc is an average based on solutions for B and V data and a primary star temperature of 5800K. Standardized light curves (not differential), radial velocities, and a spectroscopic primary star temperature are input to the pro- gram. Differential corrections were performed for each light curve band along with the velocities for two primary temperatures that span 100K. Log10d is a model parameter like many others that are adjustable in W-D. The eclipsing binary distance agrees with the Hipparcos parallax distance and is more precise.Comment: 2 pages, 1 table, International Conference: Binaries - Key to Comprehension of the Universe, Brno, Czech Republic June 8-12, 200

Nonlinear structural vibrations by the linear acceleration method

Numerical integration method for calculating dynamic response of nonlinear elastic structure

Nano-Engineering Defect Structures on Graphene

We present a new way of nano-engineering graphene using defect domains. These regions have ring structures that depart from the usual honeycomb lattice, though each carbon atom still has three nearest neighbors. A set of stable domain structures is identified using density functional theory (DFT), including blisters, ridges, ribbons, and metacrystals. All such structures are made solely out of carbon; the smallest encompasses just 16 atoms. Blisters, ridges and metacrystals rise up out of the sheet, while ribbons remain flat. In the vicinity of vacancies, the reaction barriers to formation are sufficiently low that such defects could be synthesized through the thermally activated restructuring of coalesced adatoms.Comment: 4 pages, 5 figure

Development of a 1.6-kW, 2000-volt, high- frequency dc-dc converter for ion thrustors using a modular design and an inductive energy pumping technique for conversion, regulation and protection Summary report

High-frequency dc-dc converter for ion thrustors using modular design and inductive energy pumping technique for conversion, regulation, and protectio

Motivations, expectations and experiences of Australian rural and regional planners

Despite playing an extremely important role in shaping communities, the role and contribution of planners is not widely understood or acknowledged. At the same time, there is a shortage of planners in Australia, especially in non-urban areas. Thus, though an online survey of 185 rural and regional planners, this research explores their motivations, expectations and experiences. Most enjoyed and felt confident in their role, explaining that they valued the relaxed family orientated rural lifestyle and the varied nature of the planning work. Although they sometimes felt isolated, the non-urban location provided quicker progression to senior roles, the ability to engage directly with the community and to see the consequences of their decisions. Only half felt their education had prepared them well for their role, citing gaps in terms of computerised modelling, team leadership and conflict resolution skills. Their feedback centred on providing a more practical course, focussing more on regional planning, and encouraging urban and rural experience placements. As the first study to quantifiably explore rural and regional Australian planners perceptions of their role and challenges, the findings illustrate current experiences, key planning challenges, perceived educational gaps and future priorities.Rural and regional planners; expectations; experiences; Australia