Large eddy simulation for turbulent non-premixed fuel-rich combustion in a cylindrical combustor

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El partenariado en aprendizaje-servicio de la Universidad Católica Australiana y la Universidad DePaul (Chicago)

Aquest article explica el partenariat en aprenentatge servei entre la Universitat Catòlica d'Austràlia i la Universitat DePaul (Chicago) i com aquesta associació ha enriquit l'aprenentatge servei per a ambdues institucions. Mitjançant una metodologia d'estudi de cas, explorem com dues grans institucions catòliques d'educació superior amb missions similars però diferents s'han associat per conèixer els seus enfocaments i contextos. Des del 2018, les dues universitats s'han reunit per discutir els seus programes i explorar oportunitats de col·laboració. Aquestes discussions han donat lloc a noves interpretacions i traduccions de la terminologia pedagògica en contextos australians i nord-americans i a la identificació de com la coherència de la missió pot informar les associacions entre les institucions catòliques d'educació superior. L'associació també ha donat lloc a col·laboracions contínues que han impulsat la missió de l'aprenentatge servei i la seva institucionalització a les dues universitats. L’article conclou reflexionant sobre el valor de les associacions entre les institucions catòliques d'educació superior a través de les fronteres nacionals i el valor d'explorar mútuament la missió, els principis i la pràctica mentre es busca una major institucionalització de l'aprenentatge servei. És a dir, aprenentatge servei en benefici mutu i per a la transformació de la comunitat i la universitat.In this paper, we report on the service-learning partnership between Australian Catholic University and DePaul University (Chicago) and how this partnership has enriched the scholarship of service-learning for both institutions. Using a case study methodology, we explore how two large Catholic Higher Education Institutions (CHEIs) with similar, yet distinct missions have partnered to learn about each other’s approaches and contexts. Since 2018, the SteansCenter for Community-Based Service-learning and Community Service Studies (DePaul) and ACU Engagement, the central agency responsible for supporting the extensive service-learning program at ACU, have met to discuss their programs and explore opportunities for collaboration. These discussions have led to new understandings and translations in the pedagogical terminology across Australian and US contexts and the identification of how mission coherence can inform partnerships between CHEIs. The partnership has also led to ongoing collaborations that have furthered the service-learning mission and institutionalisation of both universities. The paper concludes by reflecting upon the value of partnerships between CHEIs across national boundaries and the value of mutually exploring mission, principles, and practice as the field seeks further institutionalisation of service-learning. That is, service-learning for the mutual benefit and transformation of the community and university.Este artículo explica la relación de partenariado de aprendizaje-servicio entre la Universidad Católica de Australia y la Universidad DePaul (Chicago) y cómo esta asociación ha enriquecido el aprendizaje servicio para ambas instituciones. Mediante una metodología de estudio de caso, exploramos cómo dos grandes instituciones católicas de educación superior con misiones similares pero diferentes se han asociado para conocer sus enfoques y contextos. Desde 2018, ambas universidades se han reunido para discutir sus programas y explorar oportunidades de colaboración. Estas discusiones han dado lugar a nuevas interpretaciones y traducciones de la terminología pedagógica en contextos australianos y estadounidenses y a la identificación de cómo la coherencia de la misión puede informar a las asociaciones entre las instituciones católicas de educación superior. La asociación también ha dado lugar a colaboraciones continuas que han impulsado la misión del aprendizaje-servicio y su institucionalización en ambas universidades. El artículo concluye reflexionando sobre el valor de las asociaciones entre las instituciones católicas de educación superior a través de las fronteras nacionales y el valor de explorar mutuamente la misión, principios y práctica mientras se busca una mayor institucionalización del aprendizaje-servicio. Es decir, aprendizaje-servicio en beneficio mutuo y para la transformación de la comunidad y la universidad

Virus-like particles associated with marine mussel mortalities in New Zealand

Green-lip mussel Pema canaliculus spat (15 to 30 mm length) in the outer Marlborough Sounds, New Zealand, suffered 50 to 100% mortality during January to April 1994 (summer/autumn) following thinning and reseeding of the mussel lines by farmers. Adult mussel mortalities of 2 to 5 % continued from February to early May 1994. Histological examination showed extensive haemocytosis and multifocal liquefaction necrosis of interstitial cells, basal cells and digestive tubule epithelial cells. Sloughed pyknotic or karyolytic digestive tubule epithelial cells formed characteristic rounded granular bodies 10 to 15 μm diameter both in digestive tubules and free in lesions . No viral inclusion bodies were observed. Ultrastructural examination showed highly modified rough endoplasmic reticulum associated with small, 25 to 45 nm diameter, electron- dense uncoated virus-like particles Identical cell damage and virus-like particles were subsequently found in monbund adult (75 to 110 mm length) P canaliculus and stunted (25 to 4 7 mm length) subt1dal Mvtilus galloprovincialis from the same area. Following purfication of extracts of the moribund spat by isopycnic centrifugation in CsCJ, large numbers of 25 nm diameter, unenveloped, virus particles were seen by electron microscopy. These particles had a density of 1.364 g cm- 3 A broad band at a density expected for enveloped particles (1.21to1.24 g cm 1 ) was also observed but contained few virus-like particles. Cell damage and mussel mortalities are thus likely due to a small unenveloped virus

Large eddy simulation of a turbulent non-premixed propane-air reacting flame in a cylindrical combustor

Large Eddy Simulation (LES) is applied to investigate the turbulent non-premixed combustion flow, including species concentrations and temperature, in a cylindrical combustor. Gaseous propane (C3H8) is injected through a circular nozzle which is attached at the centre of the combustor inlet. Preheated air with a temperature of 773 K is supplied through the annulus surrounding of this fuel nozzle. In LES a spatial filtering is applied to the governing equations to separate the flow field into large-scale and small-scale eddies. The large-scale eddies which carry most of the turbulent energy are resolved explicitly, while the unresolved small-scale eddies are modelled using the Smagorinsky model with Cs = 0.1 as well as dynamically calibrated Cs. The filtered values of the species mass fraction, temperature and density, which are the functions of the mixture fraction (conserved scalar), are determined by integration over a beta probability density function (β-PDF). The computational results are compared with those of the experimental investigation conducted by Nishida and Mukohara. According to this experiment, the overall equivalence ratio of 0.6, which is calculated from the ratio of the air flow rate supplied to the combustion chamber to that of the stoichiometric reaction, is kept constant so that the turbulent combustion at the fuel nozzle exit starts under the fuel-rich conditions

Disease threats to farmed green-lipped mussels Perna canaliculus in New Zealand: Review of challenges in risk assessment and pathway analysis

The endemic green-lipped mussel (GLM) Perna canaliculus is a key cultural and economic species for New Zealand. Unlike other cultured shellfish species, GLMs have experienced relatively few disease issues. The apparent absence of diseases in both wild and farmed GLM populations does not preclude risks from environmental changes or from the introduction of overseas mussel pathogens and parasites. Potential for disease exchange between the GLM and other mytilid species present in New Zealand has yet to be elucidated. After reviewing and discussing relevant scientific literature, we present an initial assessment of GLM vulnerability to disease threats and the potential risk pathways for mussel pathogens and parasites into New Zealand and highlight a number of challenges. These include knowledge gaps relevant to GLM susceptibility to exotic pathogens and parasites, risk pathways into New Zealand and biosecurity risk associated with domestic pathways. Considerations and findings could potentially apply to other farmed aquatic species with limited distribution range and/or low disease exposure

A reanalysis of the luminosities of clusters of galaxies in the EMSS sample with 0.3 < z < 0.6

The X-ray luminosities of the Einstein Extended Medium Sensitivity Survey (EMSS) clusters of galaxies with redshifts 0.3<z<0.6 are remeasured using ROSAT PSPC data. It is found that the new luminosities are on average 1.18 +/- 0.08 times higher than previously measured but that this ratio depends strongly on the X-ray core radii we measure. For the clusters with small core radii, in general we confirm the EMSS luminosities, but for clusters with core radii >250 kpc (the constant value assumed in the EMSS), the new luminosities are 2.2 +/- 0.15 times the previous measurements. The X-ray luminosity function (XLF) at 0.3<z<0.6 is recalculated and is found to be consistent with the local XLF. The constraints on the updated properties of the 0.3<z<0.6 EMSS sample, including a comparison with the number of clusters predicted from local XLFs, indicate that the space density of luminous, massive clusters has either not evolved or has increased by a small factor ~2 since z=0.4. The implications of this result are discussed in terms of constraints on the cosmological parameter Omega_0.Comment: 12 pages, 7 figures. Accepted for publication in MNRA

On the impact of tropical cyclones on Rossby wave packets: A climatological perspective

Many studies have highlighted the importance of recurving tropical cyclones (TCs) in triggering Rossby waves. This study investigates the impact of western North Pacific (WNP), south Indian Ocean, and North Atlantic recurving TCs on the amplitude and frequency of synoptic-scale Rossby wave packets (RWPs) over a 30-yr period. The results indicate a significant increase of RWP frequency downstream of WNP and south Indian Ocean TCs. A statistically significant RWP amplitude anomaly downstream of these TCs suggests that RWPs, which are associated with TCs, are stronger than those that generally occur in midlatitudes. North Atlantic TCs do not seem to be associated with a statistically significant increase in RWP frequency and amplitude downstream. Processes that contribute to Rossby wave amplification are identified by creating composites for WNP TCs with and without downstream development. Potential vorticity, eddy kinetic energy, and quasigeostrophic forcing diagnostics highlight dynamical mechanisms that contribute to the synergistic interaction between the TC and the midlatitude flow. The existence of an upstream Rossby wave favors a downstream development. Diabatically enhanced upper-level divergent flow that can be attributed to the nonlinear interaction between the TC and the midlatitude flow impedes the eastward propagation of the upstream trough, amplifies the downstream ridge, and intensifies the jet. The amplified midlatitude flow provides upper-level forcing, which helps to maintain the predominantly diabatically driven divergent flow. Forecast uncertainties that are related to these complex TC–midlatitude flow interactions may spread into downstream regions. A climatological analysis of ensemble reforecast data emphasizes the importance of TC–midlatitude flow interactions and Rossby wave amplification on downstream predictability. </jats:p

Projected pH reductions by 2100 might put deep North Atlantic biodiversity at risk

This study aims to evaluate the potential for impacts of ocean acidification on North Atlantic deep-sea ecosystems in response to IPCC AR5 Representative Concentration Pathways (RCPs). Deep-sea biota is likely highly vulnerable to changes in seawater chemistry and sensitive to moderate excursions in pH. Here we show, from seven fully coupled Earth system models, that for three out of four RCPs over 17% of the seafloor area below 500 m depth in the North Atlantic sector will experience pH reductions exceeding ?0.2 units by 2100. Increased stratification in response to climate change partially alleviates the impact of ocean acidification on deep benthic environments. We report on major pH reductions over the deep North Atlantic seafloor (depth &gt;500 m) and at important deep-sea features, such as seamounts and canyons. By 2100, and under the high CO2 scenario RCP8.5, pH reductions exceeding ?0.2 (?0.3) units are projected in close to 23% (~15%) of North Atlantic deep-sea canyons and ~8% (3%) of seamounts – including seamounts proposed as sites of marine protected areas. The spatial pattern of impacts reflects the depth of the pH perturbation and does not scale linearly with atmospheric CO2 concentration. Impacts may cause negative changes of the same magnitude or exceeding the current target of 10% of preservation of marine biomes set by the convention on biological diversity, implying that ocean acidification may offset benefits from conservation/management strategies relying on the regulation of resource exploitation

An NMR-based nanostructure switch for quantum logic

We propose a nanostructure switch based on nuclear magnetic resonance (NMR) which offers reliable quantum gate operation, an essential ingredient for building a quantum computer. The nuclear resonance is controlled by the magic number transitions of a few-electron quantum dot in an external magnetic field.Comment: 4 pages, 2 separate PostScript figures. Minor changes included. One reference adde

The principles and practices of educational neuroscience: commentary on Bowers (2016)

In his recent critique of Educational Neuroscience, Bowers argues that neuroscience has no role to play in informing education, which he equates with classroom teaching. Neuroscience, he suggests, adds nothing to what we can learn from psychology. In this commentary, we argue that Bowers’ assertions misrepresent the nature and aims of the work in this new field. We suggest that, by contrast, psychological and neural levels of explanation complement rather than compete with each other. Bowers’ analysis also fails to include a role for educational expertise – a guiding principle of our new field. On this basis, we conclude that his critique is potentially misleading. We set out the well-documented goals of research in Educational Neuroscience, and show how, in collaboration with educators, significant progress has already been achieved, with the prospect of even greater progress in the future