9,491 research outputs found
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Team-oriented process programming
Team-oriented process programming promises to provide significant support for the planning, directing, and controlling of software engineering projects. In this paper we apply process programming to software engineering teams and show how this can provide powerful new capabilities for the management of software projects. We identify key issues which must be addressed to apply process programming to teams, and present our vision for team-oriented process programming
Tidal End States of Binary Asteroid Systems with a Nonspherical Component
We derive the locations of the fully synchronous end states of tidal
evolution for binary asteroid systems having one spherical component and one
oblate- or prolate-spheroid component. Departures from a spherical shape, at
levels observed among binary asteroids, can result in the lack of a stable
tidal end state for particular combinations of the system mass fraction and
angular momentum, in which case the binary must collapse to contact. We
illustrate our analytical results with near-Earth asteroids (8567) 1996 HW1,
(66391) 1999 KW4, and 69230 Hermes.Comment: 13 pages, 3 figures, published in Icaru
Book Review: Art in Focus
Book review for Art In Focus, Gene Mittler, Glencoe Publishing Company, Peoria, IL, 1986
Supercritical CO2 geothermal energy system analysis
There has been considerable interest in the possibility of using supercritical carbon dioxide (SCCO2) as a geothermal heat mining fluid instead of water. Some favourable fluid transport properties may prove to give an advantage in some circumstances. The low viscosity to density ratio suggests higher mass flow rates and better suitability to low permeability to low permeability reservoirs may be possible. Higher frictional losses in the wellbores may degrade that advantage.
It has been shown that SCCO2 has the potential to utilise buoyancy effects such that a thermosiphon circulates the geothermal fluid without the need for a pump. In addition, it has been proposed that SCCO2 could be used to drive a turbine directly rather than a conventional binary heat exchange system. This could dramatically reduce surface plant complexity and cost.
This study details the creation of a Matlab model of the subsurface circuit of geothermal fluid. After establishing a reference case to study general fluid and system behaviour, the model is used to test and compare the effects of wellbore diameter variation, reservoir depth, permeability and temperature on the net exergy and thermal efficiency using each of water and SCCO2.
For the specific test cases, SCCO2 was shown to perform significantly better than water with increased well bore diameter, low permeability and low temperature reservoirs. The performance was found to degrade with shallower reservoirs; although this leads to observations that the SCCO2 system operates on a narrow band of efficiency which could make the system less robust than comparable water based system
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Smart labs and social practice: social tools for pervasive laboratory workspaces: a position paper
The emergence of pervasive and ubiquitous computing stimulates a view of future work environments where sharing of information, data and knowledge is easy and commonplace, particularly in highly interactive settings. Much of the work in this area focuses on tool development to support activities such as data collection, data recording and sharing, and so on. We are interested in this kind of technical development, which is both challenging and essential for science communities. But we are also interested in a broader interpretation of knowledge sharing and the human/social side of tools we develop to support this. We are keen to know more about how groups of different kinds of scientists can make their work understandable and shareable with each other in a multidisciplinary setting. This is a complex task because boundaries and barriers can emerge between disciplines engendered by differences in discourses and practices, which may not easily translate into other discipline areas. In the worst case, there may be some hostility between disciplines, or at least doubt and scepticism. Nevertheless, sharing approaches to research, research expertise, data and methods across disciplines can be a very fruitful exercise, and encouragement to engage in this activity is particularly pertinent in the digital era. Issues of privacy and security are also key aspects – knowing when and how to release data or information to other groups is crucial to providing a safe environment for people to work, and there are several sensitivities to be explored here.
In this paper we describe an evolving situation that captures many of these issues, which we aim to track longitudinally
Asteroid Systems: Binaries, Triples, and Pairs
In the past decade, the number of known binary near-Earth asteroids has more
than quadrupled and the number of known large main belt asteroids with
satellites has doubled. Half a dozen triple asteroids have been discovered, and
the previously unrecognized populations of asteroid pairs and small main belt
binaries have been identified. The current observational evidence confirms that
small (<20 km) binaries form by rotational fission and establishes that the
YORP effect powers the spin-up process. A unifying paradigm based on rotational
fission and post-fission dynamics can explain the formation of small binaries,
triples, and pairs. Large (>20 km) binaries with small satellites are most
likely created during large collisions.Comment: 31 pages, 12 figures. Chapter in the book ASTEROIDS IV (in press
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