6,914 research outputs found
Samuel Dorris Dickinson papers
No full textThe Samuel Dorris Dickinson papers contain the professional and personal records of archaeologist, journalist, and author Samuel Dorris Dickinson
Portrait of author David Foster at the National Library of Australia, Canberra, 8 June 2011 /
No full textTitle from acquisitions documentation.; Part of the collection: Portraits of author David Foster at the National Library of Australia, Canberra, 8 June 2011.; Acquired in digital format; access copy available online.; Mode of access: Online.; Photographed by a staff member of the National Library of Australia
Author David Foster with academic Jeff Doyle at the National Library of Australia, Canberra, 8 June 2011 /
No full textTitle from acquisitions documentation.; Part of the collection: Portraits of author David Foster at the National Library of Australia, Canberra, 8 June 2011.; Acquired in digital format; access copy available online.; Mode of access: Online.; Photographed by a staff member of the National Library of Australia
Author David Foster and academic Jeff Doyle at the National Library of Australia, Canberra, 8 June 2011 /
No full textTitle from acquisitions documentation.; Part of the collection: Portraits of author David Foster at the National Library of Australia, Canberra, 8 June 2011.; Acquired in digital format; access copy available online.; Mode of access: Online.; Photographed by a staff member of the National Library of Australia
The variability of marine sediment erodibility with depth: Centimetric scale effects detected from portable erosion flume tests
No full textA portable erosion flume has been developed that is capable of estimating erosion threshold and erosion rate relationships for fine-grained specimens over the depth of a typical sample tube. This newly-designed apparatus is a recirculating flume capable of generating steady currents over the exposed section of the sample. In this paper, the erosion properties of two marine sediments have been determined and show a significant systematic variation with depth at centimetre scale that would have implications for the potential need for scour protection engineering. The tests showed that the critical erosion onset velocity doubled over the upper 200 mm of each sample, and the erosion rate fell by an order of magnitude. The increased erosion resistance with depth is consistent with the general trend of erodibility reducing with decreasing moisture content. Ignoring this depth effect when selecting design values of the erosion properties could lead to erroneous predictions of scour rate and extent around subsea structures, and unnecessary scour protection engineering costs
Synchronised multi-scale image analysis of soil deformations
No full textNew apparatus and techniques for performing synchronised multi-scale particle image velocimetry or digital image correlation (PIV/DIC) soil deformation measurements have been developed. A central camera records a full field of view (FoV) of the model capturing the ‘macro’ deformation mechanism and the boundaries of the model. Simultaneously, an adjacent slave camera records a subset of the full FoV capturing the ‘micro’ soil response in a region of special interest, such as under the corner of footing. The ‘micro’ FoV images have higher resolution in terms of particle/pixel size ratio (d/p), resulting in the ability to measure localised deformations that are invisible to lower resolution images. Recommendations are made with respect to appropriate subset size and spacing for highresolution images. A photogrammetric correction process requiring a small number of static control points is proposed and the performance is validated against a conventional photogrammetric calibration utilising a large array of static control points. Lastly, results from a validation experiment are presented comparing the PIV/DIC output from the ‘macro’ and ‘micro’ FoV, illustrating that: (a) the photogrammetric correction method proposed is robust and (b) that there has been an improvement in spatial resolution of the strain measurements that can be obtained through the ‘micro’ FoV camera.</p
Shallow penetrometer tests: Theoretical and experimental modelling of the rotation stage
No full textShallow penetrometers are a new type of device that measures the properties of surficial offshore sediments via multi-phase tests involving penetration, dissipation, and rotation stages. In fine-grained soils such as silts and clays, these testing stages yield properties relevant to subsea pipeline and shallow foundation design; namely, undrained strength, consolidation, and interface friction. This paper describes the fundamentals of the rotation stage, including models required for data interpretation, encompassing both a total and an effective stress framework. Additionally, new relationships to evaluate the pore pressure scaling factor, which is a key interpretation parameter required to convert discrete measurements of pore pressure on the penetrometers to an average pore pressure over the contact area, are developed based on large-deformation finite element simulations. Results from an experimental campaign using kaolin clay samples are presented, illustrating the potential of the devices to rapidly and repeatably measure interface friction properties of fine-grained sediments offshore. The results compare well with comparative measures obtained from shear box tests conducted at similarly low effective stress levels. Recommendations regarding future in situ applications are given at end of the paper.</p
Improvements in plate anchor capacity due to cyclic and maintained loads combined with consolidation
No full textPlate anchor technology is an efficient solution for mooring offshore floating facilities for oil and gas or renewable energy facilities. The anchor is typically subjected to a maintained load component and intermittent episodes of cyclic loading throughout the design life. These loads, and the associated shearing, remoulding and consolidation processes, cause changes in the anchor capacity, particularly in soft fine-grained soils. The changing anchor capacity affects the mooring performance by changing the safety margin and also the overall system reliability. In this paper the changing anchor capacity in reconstituted normally-consolidated natural carbonate silt was assessed through a series of beam centrifuge tests on horizontally loaded circular plate anchors. The results demonstrate that full consolidation under a typical maintained load leads to a 50% gain in the anchor capacity, and subsequent cyclic loading and reconsolidation can triple this increase. An effective stress framework based on critical state concepts is employed to explain and support the experimental observations. This study shows that when viewed from a whole-life reliability perspective, maintained and cyclic loading provide a long-term enhancement of anchor capacity in soft fine-grained soils. This beneficial effect is currently overlooked in design practice, but can be predicted using the framework shown here, which can form the basis for a digital twin that monitors the through-life integrity of a plate anchor
Portrait of Paul Ham at the National Library of Australia, 15 November 2011 /
No full textTitle from nformation supplied by photographer.; Part of the collection: Podcast photograph of author Paul Ham at the National Library of Australia, 15 November 2011.; Mode of access: Online.; Photographed by a staff member of the National Library of Australia
Samuel Oshimi-John
No full textabstract: Samuel was nine years old when he left his village because of the fighting and bombing around his village.
“Lost Boys Found” is an ongoing, interdisciplinary project that is collecting, recording and archiving the oral histories of the Lost Boys/Girls of Sudan. The collection is a work-in-progress, seeking to record the oral history of as many Lost Boys/Girls as are willing, and will be used in a future book.Age: 30Region: Upper NileThis picture and bio was donated to the "Lost Boys Found" oral history project from The Arizona Lost Boys Cente
- …
