Computation of leading-edge vortex flows

The simulation of the leading edge vortex flow about a series of conical delta wings through solution of the Navier-Stokes and Euler equations is studied. The occurrence, the validity, and the usefulness of separated flow solutions to the Euler equations of particular interest. Central and upwind difference solutions to the governing equations are compared for a series of cross sectional shapes, including both rounded and sharp tip geometries. For the rounded leading edge and the flight condition considered, viscous solutions obtained with either central or upwind difference methods predict the classic structure of vortical flow over a highly swept delta wing. Predicted features include the primary vortex due to leading edge separation and the secondary vortex due to crossflow separation. Central difference solutions to the Euler equations show a marked sensitivity to grid refinement. On a coarse grid, the flow separates due to numerical error and a primary vortex which resembles that of the viscous solution is predicted. In contrast, the upwind difference solutions to the Euler equations predict attached flow even for first-order solutions on coarse grids. On a sufficiently fine grid, both methods agree closely and correctly predict a shock-curvature-induced inviscid separation near the leeward plane of symmetry. Upwind difference solutions to the Navier-Stokes and Euler equations are presented for two sharp leading edge geometries. The viscous solutions are quite similar to the rounded leading edge results with vortices of similar shape and size. The upwind Euler solutions predict attached flow with no separation for both geometries. However, with sufficient grid refinement near the tip or through the use of more accurate spatial differencing, leading edge separation results. Once the leading edge separation is established, the upwind solution agrees with recently published central difference solutions to the Euler equations

High impact activities in parks: best management practice and future research

Off-road driving, horseriding, rock climbing and similar activities can be lucrative for tour operators and important for local recreational groups, but contentious for management of national parks and protected areas, both because of safety and liability and because of potentially high environmental impacts. These include spreading weeds and pathogens, starting fires and crushing bird nests on beaches, amongst many others. In Australia as elsewhere, off-road vehicles and horses are allowed only in some places in some parks, and often only under permit. We have very little reliable scientific information to-date on just how serious these impacts may be, and on how well they might be managed through minimal-impact practices such as vehicle washdowns, stockfeed processing and seasonal closures. Such information can only be obtained through site specific ecological studies of the plants, animals and watercourses likely to be affected, differentiating tourism impacts from natural causes and fluctuations. This report examines management strategies for these activities worldwide and in Australia. Suggestions for best management practice and future research agendas are set

Discrepancy Analysis Between Close-Range Photogrammetry And Terrestrial LiDAR

This study presents a comparison of building measurements performed on 3D models generated by two different approaches. In one approach, the models were produced via close-range photogrammetry. Such models are based on still-frame photographs that are, post-processed with commercially available photogrammetric software. In the second approach, 3D point-cloud models were generated via laser scanning. For this purpose, three case studies were conducted. The first was a simple one story structure, the second was a multi-story Maya ruin, and the third was an earth filled terrace. Several benchmarks within a closed traverse were established to serve as standard georeference points for all accuracy comparisons. Several physical target points were then marked on the exterior walls of the structure. They are referred here as reference wall points. The reference wall points were then measured with a total-station instrument. After photographs were taken and laser scanning of the structure performed, the coordinates of the reference wall points were also determined from the respective models. The coordinates were then compared with the ones obtained with the total-station instrument. Coordinates and distances from each procedure were compared to determine relative discrepancies and accuracies. The results of this study demonstrate that the close-range photogrammetry can provide accurate enough information to be used as an alternative for total stations or laser scanners when measuring buildings or other relatively small projects

Linking anthropogenic resources to wildlife-pathogen dynamics: a review and meta-analysis

Urbanisation and agriculture cause declines for many wildlife, but some species benefit from novelresources, especially food, provided in human-dominated habitats. Resulting shifts in wildlife ecol-ogy can alter infectious disease dynamics and create opportunities for cross-species transmission,yet predicting host–pathogen responses to resource provisioning is challenging. Factors enhancingtransmission, such as increased aggregation, could be offset by better host immunity due toimproved nutrition. Here, we conduct a review and meta-analysis to show that food provisioningresults in highly heterogeneous infection outcomes that depend on pathogen type and anthropo-genic food source. We also find empirical support for behavioural and immune mechanismsthrough which human-provided resources alter host exposure and tolerance to pathogens. Areview of recent theoretical models of resource provisioning and infection dynamics shows thatchanges in host contact rates and immunity produce strong non-linear responses in pathogen inva-sion and prevalence. By integrating results of our meta-analysis back into a theoretical frame-work, we find provisioning amplifies pathogen invasion under increased host aggregation andtolerance, but reduces transmission if provisioned food decreases dietary exposure to parasites.These results carry implications for wildlife disease management and highlight areas for futurework, such as how resource shifts might affect virulence evolution

An epidemiological assessment of the prevalence and referral mechanism of orofacial diseases to the only tertiary dental care institution in Hong Kong - a pilot study

Abstract no. 0111published_or_final_versio

Capabilities of the Skylab-A spectrometer (S191) for remote sensing of surface targets in the thermal-infrared spectral region

The effects of some of the factors which fundamentally limit the amount of information which can be deduced from spectrometer (S191) measurements, made from the orbital altitude of Skylab-A, of the thermal-infrared power radiated into space from typical surface targets are discussed. The particular significance of this spectral region is that the power radiated at night is comparable in intensity to that in daylight. Calculations were made which simulate the quality of spectrometer data that could be expected from spectral measurements made in space, of the thermal-infrared radiation emitted from typical rocks on the surface. The results indicate that the reststrahlen structure in these spectra is not distinctive enough to permit reliable identification of the rocks. This conclusion is confirmed by relevant data which have already been obtained from aircraft and spacecraft

A proposed governance model for the adoption of geoparks in Australia

Purpose Good governance is crucial in establishing and managing geoparks and is a requirement by UNESCO if global status is to be achieved. Australia has three levels of government, government agencies and not for profit organisations that can assist in the reintroduction of geoparks to Australia. This paper examines a range of governance models used by UNESCO Global Geoparks. Design/methodology/approach This paper explores mechanisms that could be applied in the reintroduction of geoparks into Australia and considers how future geoparks might be managed. The suggested model is based on a review of existing UNESCO Global Geopark governance and their management structures. Findings This paper reviews the opportunities for engaging with Australian organisational stakeholders to support geoparks and proposes a model that would be suitable for adoption in Australia. Originality/value This paper examines a range of governance models applied to geopark development. It reviews the opportunities for engaging with Australian organisational stakeholders to support geoparks and proposes a model that would be suitable for adoption in Australia. Such an account has not previously been undertaken nor a satisfactory model proposed for the Australian situation. This is the first time that a comprehensive model for geopark governance has been proposed for Australia

Geoparks – learnings from Australia

Purpose This study aims to provide an overview of the current socio-political geopark situation in Australia and set this into a global context. In addition, the authors consider this information to be useful for all stakeholders involved in geopark research and development. An analysis of constraints is set alongside stakeholder views collected from remote rural Western Australia. The authors also place Australia in a global context in regard to the future of geoparks. Design/methodology/approach Vital contextual information regarding the tourism significance of geoparks is sourced from key literature. The authors analyse and report on the situation surrounding the current lack of enthusiasm for the geopark concept by the federal government and states in Australia. The authors also report positive rural community stakeholder views on geopark development from regional Western Australia. Findings While Australian federal, as well as state governments have yet to accept geoparks, stakeholder research in Western Australia supports the idea of geopark development. Learnings articulated in this viewpoint are relevant to any country pursuing and initiating the geopark concept. The authors posit that global geopark development can become a vital strategy in post-COVID-19 tourism recovery planning. Originality/value Australia currently does not have a United Nations Educational, Scientific and Cultural Organisation (UNESCO)-recognised geopark. Accordingly, the authors present a case for geopark development, while at the same time exploring the socio-political reasons behind the lack of geopark implementation in Australia. The authors consider the future of geoparks in the global context and reiterate the point that geoparks are important for COVID-19 recovery of tourism and in regard to UNESCO's Sustainable Development Goals for 2030