1,721,958 research outputs found
White, D J, 427966
No full textThis record was harvested from a previous catalogue system and will be withdrawn in 2025. Information in this record may be superseded or incomplete. Visit this record in UMA's new catalogue at: https://archives.library.unimelb.edu.au/nodes/view/425288Surname: WHITE. Given Name(s) or Initials: D J. Military Service Number or Last Known Location: 427966. Missing, Wounded and Prisoner of War Enquiry Card Index Number: 55887.251151
Item: [2016.0049.57549] "White, D J, 427966
White, D J P, NX31624
No full textThis record was harvested from a previous catalogue system and will be withdrawn in 2025. Information in this record may be superseded or incomplete. Visit this record in UMA's new catalogue at: https://archives.library.unimelb.edu.au/nodes/view/425340Surname: WHITE. Given Name(s) or Initials: D J P. Military Service Number or Last Known Location: NX31624. Missing, Wounded and Prisoner of War Enquiry Card Index Number: 41378.251203
Item: [2016.0049.57601] "White, D J P, NX31624
CPT equipment: Recent advances and future perspectives
No full textThe basic configuration of the cone penetrometer test (CPT) has remained constant for half a century since the electric piezocone became widespread in the 1970s and the dimensions and test protocols were standardized soon after. The results of a conventional CPT performed today might be indistinguishable from a test conducted at the same location in 1972, aside from improved data logging and presentation. This discussion reflects on advances in CPT and other penetrometer equipment presented at this conference and in the recent literature, and presents discussion points to be considered during the event. Two general observations emerge: (i) advances in instrumentation, sensing and mechanical engineering have created a vast range of variations on the conventional CPT, providing excitement for technologists, researchers and a small subset of users; (ii) the conventional CPT is heavily standardized, commoditized and automated, and is progressively replacing the SPT in onshore practice. The result is a dispersion of practice: the majority of civil engineers base their ground characterization on a durable 1970s technology, updated with automation and improved data quality, while a minority are enjoying exploration of non-standard innovations – with mixed levels of impact. This conference provides a chance for us to (i) reflect where our activities sit in this spectrum, (ii) enjoy learning about recent advances, and (iii) debate how we will characterize the ground in another 50 years.</p
Xenotransplantation
No full textXenotransplantation of pig organs into humans represents an attractive solution to the worldwide organ shortage. The survival of pig organs in primates has so far primarily been hampered by hyperacute rejection of the xenograft. The immunological mechanisms which underlie hyperacute rejection have recently been clarified. These important elucidations, together with the introduction of genetic engineering in the field of transplantation, have led to the production of genetically manipulated animals with organs that are now not susceptible to the immunological factors responsible for hyperacute rejection. In this article the recent advances in the understanding of hyperacute rejection are reviewed and the latest biomolecular approaches to overcome hyperacute rejection are described
Elastic solutions for consolidation around seabed pipelines
No full textThe build-up of pipe-soil resistance that can be mobilized on a seabed pipeline, particularly in the axial direction, is affected by consolidation of the seabed beneath the pipeline after it is laid. On fine-grained soils the consolidation period may extend well beyond the laying period, and involve a significant gain in pipe-soil resistance: a process analogous to the set-up of piles driven in clay. The available level of pipe-soil resistance affects many aspects of pipeline design, such as stability on route curves and down slopes, geohazard vulnerability, lateral buckling and axial walking behaviour. This paper considers consolidation around on-bottom pipelines through a numerical study, supported by field data. The soil is modeled as an elastic material with coupled Biot consolidation. Pipe embedments of up to 0.5 diameters have been considered and the effect of soil berms adjacent to the pipe, formed of the displaced soil, has been explored. The solutions and guidance provided in this paper allow pipeline designers to estimate the 'set-up' periods over which the effective stress at the pipe-soil interface will rise in the period after laying, indicating the build-up of available axial pipe-soil resistance. The results account for the enhancement of this resistance through a 'wedging' action. The dissipation process is retarded by a factor of up to 2 if the displaced soil forms a berm that is collapsed against the pipe wall. Similar solutions for the analogous situation of consolidation ('set-up') around driven piles have existed for many years. This paper provides the equivalent design tool for on-bottom pipelines.</p
Numerical modelling of plate anchors under sustained load: the enhancement of capacity from consolidation
No full textEmbedded plate anchors can be used to moor floating offshore facilities. In taut mooring systems, a sustained tension carried by the anchors affects their long-term capacity due to consolidation effects in the soil surrounding the anchor. The resulting gain in capacity provides a potential basis for more efficient anchoring system design. To quantify this effect, and to understand the underlying mechanism, a systematic numerical study has been performed, to capture the effect of sustained loading and consolidation on soil failure mechanisms around an embedded plate anchor. The modified Cam clay model is used, to capture the effect of consolidation on soil strength, and also to faithfully model the process by which a water-filled gap forms under the plate, due to a loss of contact between the plate and the soil, with seepage into the gap zone. A critical observation is the load transfer process when such a gap forms beneath the plate after the applied tension causes the effective stress to fall to zero. The formation of this gap is shown to depend, in a systematic way, on the sustained tension, or preload, the soil strength ratio, the relative sharing of the anchor load between compression above the plate and tension below, as well as the embedded depth of the anchor. Simple relationships that capture these mechanisms are provided, linking the net change in soil strength above and below the anchor to the change in undrained capacity. As an example, it is shown that in soft normally-consolidated clays, a sustained preload of 60 % of the initial capacity, can create a 25 % gain in capacity, at which point the factor of safety is raised from 1/0.6 = 1.67 to 2. This gain is only available for anchors embedded by more than twice their diameter. At shallower embedment, the loss of strength in the unloaded soil beneath the anchor outweighs the gain in strength in the smaller zone of soil above the anchor, and the consolidation process causes a net weakening.</p
Assessment of the consolidated breakout response of partially embedded subsea pipelines
No full textThe changing soil strength due to consolidation around a subsea pipeline can alter the lateral breakout resistance. Results of elasto-plastic coupled consolidation finite-element analyses are presented that quantify the effect of consolidation on the undrained breakout resistance and trajectory of partially embedded seabed pipelines. Breakout resistance is presented in terms of failure envelopes in vertical-horizontal load space, which also allow the trajectory of the pipe during breakout to be determined by normality. Observed responses for consolidated undrained breakout are described by simple algebraic expressions as a function of initial pipe embedment, pipe self-weight (and consequent consolidation pressure) and breakout load path. Consolidation and the associated enhancement of the shear strength of the surrounding soil can have a significant effect on the breakout response. The assumption in current practice of unconsolidated undrained soil behaviour may lead to underestimation of pipeline breakout resistance and inaccurate prediction of the trajectory of the pipe during breakout.</p
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
- …
