Computational experience with a three-dimensional rotary engine combustion model

A new computer code was developed to analyze the chemically reactive flow and spray combustion processes occurring inside a stratified-charge rotary engine. Mathematical and numerical details of the new code were recently described by the present authors. The results are presented of limited, initial computational trials as a first step in a long-term assessment/validation process. The engine configuration studied was chosen to approximate existing rotary engine flow visualization and hot firing test rigs. Typical results include: (1) pressure and temperature histories, (2) torque generated by the nonuniform pressure distribution within the chamber, (3) energy release rates, and (4) various flow-related phenomena. These are discussed and compared with other predictions reported in the literature. The adequacy or need for improvement in the spray/combustion models and the need for incorporating an appropriate turbulence model are also discussed

Analysis of rotary engine combustion processes based on unsteady, three-dimensional computations

A new computer code was developed for predicting the turbulent, and chemically reacting flows with sprays occurring inside of a stratified charge rotary engine. The solution procedure is based on an Eulerian Lagrangian approach where the unsteady, 3-D Navier-Stokes equations for a perfect gas mixture with variable properties are solved in generalized, Eulerian coordinates on a moving grid by making use of an implicit finite volume, Steger-Warming flux vector splitting scheme, and the liquid phase equations are solved in Lagrangian coordinates. Both the details of the numerical algorithm and the finite difference predictions of the combustor flow field during the opening of exhaust and/or intake, and also during fuel vaporization and combustion, are presented

Is there really a value in entrepreneurship education?

This paper considers whether entrepreneurship education has a value outside of the education institutions in which it takes place. The paper takes an indirect form of enquiry and argues that entrepreneurship education is driven by three factors; the growing emphasis on supply side policy interventions in the economy; the emphasis placed on the agency of management in the growing literature on globalisation and international reforms to public sector organisations. The paper concludes that there is a tension between the activity as descriptive and the activity as promotion and until this tension is resolved it is unlikely that there will be clarity about the value of this form of education

Properties of Hot Stars in the Wolf-Rayet galaxy NGC5253 from ISO Spectroscopy

ISO-SWS spectroscopy of the WR galaxy NGC5253 is presented, and analysed to provide estimates of its hot young star population. Our approach differs from previous investigations in that we are able to distinguish between the regions in which different infrared fine-structure lines form, using complementary ground-based observations. The high excitation nebular [SIV] emission is formed in a very compact region, which we attribute to the central super-star-nucleus, and lower excitation [NeII] nebular emission originates in the galactic core. We use photo-ionization modelling coupled with the latest theoretical O-star flux distributions to derive effective stellar temperatures and ionization parameters of Teff>38kK, logQ=8.25 for the compact nucleus, with Teff=35kK, logQ<8 for the larger core. Results are supported by more sophisticated calculations using evolutionary synthesis models. We assess the contribution that Wolf-Rayet stars may make to highly ionized nebular lines (e.g. [OIV]). From our Br(alpha) flux, the 2" nucleus contains the equivalent of approximately 1000 O7V star equivalents and the starburst there is 2-3Myr old; the 20" core contains about 2500 O7V star equivalents, with a representative age of 5Myr. The Lyman ionizing flux of the nucleus is equivalent to the 30 Doradus region. These quantities are in good agreement with the observed mid-IR dust luminosity of 7.8x10^8 L(sun) Since this structure of hot clusters embedded in cooler emission may be common in dwarf starbursts, observing a galaxy solely with a large aperture may result in confusion. Neglecting the spatial distribution of nebular emission in NGC5253, implies `global' stellar temperatures (or ages) of 36kK (4.8Myr) and 39kK (2.9 or 4.4Myr) from the observed [NeIII/II] and [SIV/III] line ratios, assuming logQ=8.Comment: 16 pages, 7 figures, uses mn.sty, to appear in MNRA

Complex networks created by aggregation

We study aggregation as a mechanism for the creation of complex networks. In this evolution process vertices merge together, which increases the number of highly connected hubs. We study a range of complex network architectures produced by the aggregation. Fat-tailed (in particular, scale-free) distributions of connections are obtained both for networks with a finite number of vertices and growing networks. We observe a strong variation of a network structure with growing density of connections and find the phase transition of the condensation of edges. Finally, we demonstrate the importance of structural correlations in these networks.Comment: 12 pages, 13 figure

Acoustic-loads research for powered-lift configurations

Data presented from large-scale model tests with jet engines having thrusts of 9 kN (2000 lb) and 36 kN (8000 lb) include acoustic loads for an externally blown wing and flap induced by a TF34 jet engine, an upper surface blown (USB) aircraft model in a wind tunnel, and two USB models in static tests. Comparisons of these results with results from acoustic loads studies on configurations of other sizes are made and the implications of these results on interior noise and acoustic fatigue are discussed

Questions of importance to the conservation of biological diversity: answers from the past

Paleoecological records are replete with examples of biotic responses to past climate change and human impact, but how can we use these records in the conservation of current and future biodiversity? A recently published list of (One Hundred Questions of Importance to the Conservation of Global Biological Diversity) (Sutherland et al., 2009) highlights a number of key research questions that need a temporal perspective. Many of these questions are related to the determination of ecological processes in order to assess ecosystem function and services, climate change integrated conservation strategies, and ecosystem management and restoration. However, it is noticeable that not a single contributor to this list was from the paleo-research community and that extremely few paleo-records are ever used in the development of terrestrial conservation management plans. This lack of dialogue between conservationists and the paleo-community is partially driven by a perception that the data provided by paleoecological records are purely descriptive and not of relevance to the day-to-day management and conservation of biological diversity. This paper illustrates, through a series of case-studies, how long-term ecological records (>50 years) can provide a test of predictions and assumptions of ecological processes that are directly relevant to management strategies necessary to retain biological diversity in a changing climate. This discussion paper includes information on diversity baselines, thresholds, resilience, and restoration of ecological processes

Regulation of activin type I receptor function by phosphorylation of residues outside the GS domain

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/117133/1/feb2s0014579397014993.pd