15,006 research outputs found
The discipline of Natural Design
If we define design work as those cognitive and practical things to which designers give their valuable effort, then our Natural Design framework allows the recording and replaying of design work. Natural Design provides a meta-structural framework that has developed through our observations of engineering design in safety and mission critical industries, such as aircraft design. Our previous work has produced parametrisable models of design work for software intensive systems, and we now look to make an initial assessment of our natural design framework for its fit to the more creative design practices. In this paper we briefly sketch the framework and subsequently attempt to locate ‘creativity’ in it. We find that, although there are good strong hooks for what the designer does, we are forced to find a role for the community of the designer in the creative process in our framework, something that was only implicit in our previous work.
Keywords:
Natural design; Engineering design; Creativity</p
Designing an online part-time Master of Philosophy with Problem Oriented Engineering
The paper reports on the application of Problem Oriented Engineering (POE) to the design of a highly innovative post-graduate research programme for the Open University, UK, a world leader in supported distance higher education. The new programme, to be launched in October 2009, is a part-time Master of Philosophy (MPhil) to be delivered entirely at a distance, supported by a blend of synchronous, asynchronous and immersive internet and web technologies. POE is a framework for engineering design under development at the Open University. After a brief description of the project and the task at hand, the paper discusses the overall engineering approach taken, key aspects of product design, the mapping between requirements and technology, and the development of one key technological component
A phenomenal basis for hybrid modelling
This work in progress extends the new mechanical philosophy from science to engineering. Engineering is the practice of organising the design and construction of artifices that satisfy needs in real-world contexts. This work shows how artifices can be described in terms of their mechanisms and composed through their observable phenomena.
Typically, the engineering of real system requires descrip- tions in many different languages: software components will be described in code; sensors and actuators in terms of their physical and electronic characteristics; plant in terms of differ- ential equations, perhaps. Another aspect of this work, then, to construct a formal framework so that diverse description languages can be used to characterise sub-mechanisms.
The work is situated in Problem Oriented Engineering, a design theoretic framework engineering defined by the first two authors
Radiative feedback and cosmic molecular gas: the role of different radiative sources
We present results from multifrequency radiative hydrodynamical chemistry
simulations addressing primordial star formation and related stellar feedback
from various populations of stars, stellar energy distributions (SEDs) and
initial mass functions. Spectra for massive stars, intermediate-mass stars and
regular solar-like stars are adopted over a grid of 150 frequency bins and
consistently coupled with hydrodynamics, heavy-element pollution and
non-equilibrium species calculations. Powerful massive population III stars are
found to be able to largely ionize H and, subsequently, He and He, causing
an inversion of the equation of state and a boost of the Jeans masses in the
early intergalactic medium. Radiative effects on star formation rates are
between a factor of a few and 1 dex, depending on the SED. Radiative processes
are responsible for gas heating and photoevaporation, although emission from
soft SEDs has minor impacts. These findings have implications for cosmic gas
preheating, primordial direct-collapse black holes, the build-up of "cosmic
fossils" such as low-mass dwarf galaxies, the role of AGNi during reionization,
the early formation of extended disks and angular-momentum catastrophe.Comment: 19 pages on MNRA
On the formation and physical properties of the Intra-Cluster Light in hierarchical galaxy formation models
We study the formation of the Intra-Cluster Light (ICL) using a semi-analytic
model of galaxy formation, coupled to merger trees extracted from N-body
simulations of groups and clusters. We assume that the ICL forms by (1) stellar
stripping of satellite galaxies and (2) relaxation processes that take place
during galaxy mergers. The fraction of ICL in groups and clusters predicted by
our models ranges between 10 and 40 per cent, with a large halo-to-halo scatter
and no halo mass dependence. We note, however, that our predicted ICL fractions
depend on the resolution: for a set of simulations with particle mass one order
of magnitude larger than that adopted in the high resolution runs used in our
study, we find that the predicted ICL fractions are ~30-40 per cent larger than
those found in the high resolution runs. On cluster scale, large part of the
scatter is due to a range of dynamical histories, while on smaller scale it is
driven by individual accretion events and stripping of very massive satellites,
, that we find to be the major contributors
to the ICL. The ICL in our models forms very late (below ), and a
fraction varying between 5 and 25 per cent of it has been accreted during the
hierarchical growth of haloes. In agreement with recent observational
measurements, we find the ICL to be made of stars covering a relatively large
range of metallicity, with the bulk of them being sub-solar.Comment: Accepted for Publication in MNRAS, 19 pages, 13 figures, 1 tabl
Simulating the formation of a proto-cluster at z~2
We present results from two high-resolution hydrodynamical simulations of
proto-cluster regions at z~2.1. The simulations have been compared to
observational results for the socalled Spiderweb galaxy system, the core of a
putative proto-cluster region at z = 2.16, found around a radio galaxy. The
simulated regions have been chosen so as to form a poor cluster with M200~10^14
h-1 Msun (C1) and a rich cluster with M200~2x10^15 h-1 Msun (C2) at z = 0. The
simulated proto-clusters show evidence of ongoing assembly of a dominating
central galaxy. The stellar mass of the brightest cluster galaxy (BCG) of the
C2 system is in excess with respect to observational estimates for the
Spiderweb galaxy, with a total star formation rate which is also larger than
indicated by observations. We find that the projected velocities of galaxies in
the C2 cluster are consistent with observations, while those measured for the
poorer cluster C1 are too low compared to the observed velocities. We argue
that the Spiderweb complex resemble the high-redshift progenitor of a rich
galaxy cluster. Our results indicate that the included supernovae feedback is
not enough to suppress star formation in these systems, supporting the need of
introducing AGN feedback. According to our simulations, a diffuse atmosphere of
hot gas in hydrostatic equilibrium should already be present at this redshift,
and enriched at a level comparable to that of nearby galaxy clusters. The
presence of this gas should be detectable with future deep X-ray observations.Comment: 6 pages, 4 figures, accepted for publication in MNRAS (Letters
ZnO/ionic liquid catalyzed biodiesel production from renewable and waste lipids as feedstocks
A new protocol for biodiesel production is proposed, based on a binary ZnO/TBAI (TBAI = tetrabutylammonium iodide) catalytic system. Zinc oxide acts as a heterogeneous, bifunctional Lewis acid/base catalyst, while TBAI plays the role of phase transfer agent. Being composed by the bulk form powders, the whole catalyst system proved to be easy to use, without requiring nano-structuration or tedious and costly preparation or pre-activation procedures. In addition, due to the amphoteric properties of ZnO, the catalyst can simultaneously promote transesterification and esterification processes, thus becoming applicable to common vegetable oils (e.g., soybean, jatropha, linseed, etc.) and animal fats (lard and fish oil), but also to waste lipids such as cooking oils (WCOs), highly acidic lipids from oil industry processing, and lipid fractions of municipal sewage sludge. Reusability of the catalyst system together with kinetic (Ea) and thermodynamic parameters of activation (∆G‡ and ∆H‡) are also studied for transesterification reaction
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