Atmospheric turbulence profiling with SLODAR using multiple adaptive optics wavefront sensors

The slope detection and ranging (SLODAR) method recovers atmospheric turbulence profiles from time averaged spatial cross correlations of wavefront slopes measured by Shack-Hartmann wavefront sensors. The Palomar multiple guide star unit (MGSU) was set up to test tomographic multiple guide star adaptive optics and provided an ideal test bed for SLODAR turbulence altitude profiling. We present the data reduction methods and SLODAR results from MGSU observations made in 2006. Wind profiling is also performed using delayed wavefront cross correlations along with SLODAR analysis. The wind profiling analysis is shown to improve the height resolution of the SLODAR method and in addition gives the wind velocities of the turbulent layers

A case study research into urban water reuse

University of Technology, Sydney. Faculty of Engineering and Information Technology.Climate change could lead to longer and more frequent droughts for Australia. The option of water reuse, being independent of rainfall variations, provides a major source of water supply security for our growing cities. A 'soft path' for water management is widely acknowledged to be the sustainable future of water management. Decentralised wastewater reuse schemes form an important supply option in this 'soft path' approach. Discussion on water reuse and its role in sustainable water resource management in Australia has been on the agenda for the last three decades. Despite its long presence on the agendas of policy makers and scientific community, promulgation of water reuse in Australia has been a rather slow process. The research efforts to date have focussed on the technological aspects of water reuse, leaving behind a gap in the area of policy and implementation aspects. This knowledge gap is even more severe when considering decentralised urban water reuse. Australian literature on decentralised reuse schemes owned and operated by entities other than the major water utilities is virtually non-existent. This research assists in bridging the knowledge gap identified above, by investigating the decentralised water reuse technique of 'water mining' in detail. The concept of water mining is defined and range of technologies available for water mining are described, along with discussion on planning and risk management aspects of such schemes. A comprehensive literature review is also provided on urban water reuse, examining centralised and decentralised water reuse in Australia. As opposed to traditional engineering line of enquiry, this research is of interdisciplinary nature, looking at socio-economic, environmental management, pricing policy, as well as technical aspects of a decentralised water reuse project. Using Beverley Park Water Reclamation Project (Sydney's first water mining scheme) as a case study, this research analyses design, planning, and implementation phases of this project. Operational risks to human as well as environmental health are also reviewed in context of the case study site. A regional economic Input Output (IO) Model for the St George- Sutherland Statistical Region is developed to analyse the economic impacts of the case study project on the local economy. In addition to the IO method, other benefit estimation methods such as Hedonic pricing and sports fields Usage Hours are also discussed in context of the case study site. On policy front, pricing of recycled water is further explored and lessons from solid waste recycling applied. The community's reluctance to accept potable reuse indicates that recycled water is not yet considered a direct substitute for virgin water. A sound water pricing regime that reflects the true costs of water and a competitive water industry is discussed as a critical policy platform for viable water recycling industry. With 21st century water management transforming into a multi-dimensional challenge of water security, a holistic multi-dimensional approach is essential. By applying different aspects of the case study inquiry lens, this research adopted a multi-dimensional approach in exploring social, economic and technical characteristics of a single water mining case study

Culture Rules: The Foundations of the Rule of Law and Other Norms of Governance

This study presents evidence about relations between national culture and social institutions. We operationalize culture with data on cultural dimensions for over 50 nations adopted from cross-cultural psychology and generate testable hypotheses about three basic social norms of governance: the rule of law, corruption, and accountability. These norms correlate systematically and strongly with national scores on cultural dimensions and also differ across cultural regions of the world. Regressions indicate that quantitative measures of national culture are alone remarkably predictive of governance, that economic inequality and British heritage add to predictive power, but that economic development and other factors add little. The results suggest a framework for understanding the relations between fundamental institutions of social order as well as policy implications for reform programs in transition economies.http://deepblue.lib.umich.edu/bitstream/2027.42/39991/3/wp605.pd

Impulsive phase solar flare X-ray polarimetry

The pioneering observational work in solar flare X-ray polarimetry was done in a series of satellite experiments by Tindo and his collaborators in the Soviet Union; initial results showed high levels of polarization in X-ray flares (up to 40%), although of rather low statistical significance, and these were generally interpreted as evidence for strong beaming of suprathermal electrons in the flare energy release process. However, the results of the polarimeter flown by the Columbia Astrophysics Laboratory as part of the STS-3 payload on the Space Shuttle by contrast showed very low levels of polarization. The largest value (observed during the impulsive phase of a single event) was 3.4% + or - 2.2%. At the same time but independent of the observational work, Leach and Petrosian (1983) showed that the high levels of polarization in the Tindo results were difficult to understand theoretically, since the electron beam is isotropized on an energy loss timescale. A subsequent comparison by Leach, Emslie, and Petrosian (1985) of the impulsive phase STS-3 result and the above theoretical treatment shows that the former is consistent with several current models and that a factor of approximately 3 improvement in sensitivity is needed to distinguish properly among the possibilities

On-sky multi-wavelength phasing of segmented telescopes with the Zernike phase contrast sensor

Future Extremely Large Telescopes will adopt segmented primary mirrors with several hundreds of segments. Cophasing of the segments together is essential to reach high wavefront quality. The phasing sensor must be able to maintain very high phasing accuracy during the observations, while being able to phase segments dephased by several micrometers. The Zernike phase contrast sensor has been demonstrated on-sky at the Very Large Telescope. We present the multi-wavelength scheme that has been implemented to extend the capture range from \pmlambda/2 on the wavefront to many micrometers, demonstrating that it is successful at phasing mirrors with piston errors up to \pm4.0 micron on the wavefront. We discuss the results at different levels and conclude with a phasing strategy for a future Extremely Large Telescope.Comment: 17 pages, 8 figures, 2 tables. Accepted for publication in Applied Optics; he final publised version is available on the OSA website: http://www.opticsinfobase.org/abstract.cfm?msid=13671

Control and Alignment of Segmented-Mirror Telescopes: Matrices, Modes, and Error Propagation

Starting from the successful Keck telescope design, we construct and analyze the control matrix for the active control system of the primary mirror of a generalized segmented-mirror telescope, with up to 1000 segments and including an alternative sensor geometry to the one used at Keck. In particular we examine the noise propagation of the matrix and its consequences for both seeing-limited and diffraction-limited observations. The associated problem of optical alignment of such a primary mirror is also analyzed in terms of the distinct but related matrices that govern this latter problem