288 research outputs found
Low-impulse blast behaviour of fibre-metal laminates
This paper presents three dimensional (3D) finite element (FE) models of the low-impulse localised blast loading response of fibre-metal laminates (FMLs) based on an 2024-O aluminium alloy and a woven glass-fibre/polypropylene composite (GFPP). A vectorized user material subroutine (VUMAT) is developed to define the mechanical constitutive behaviour and Hashinās 3D failure criteria incorporating strain-rate effects in the GFPP. In order to apply localised blast loading, a user subroutine VDLOAD is used to model the pressure distribution over the exposed area of the plate. These subroutines are implemented into the commercial finite element code ABAQUS/Explicit to model the deformation and failure mechanisms in FMLs. The FE models consider FMLs based on various stacking configurations. Both the transient and permanent displacements of the laminates are investigated. Good correlation is obtained between the measured experimental and numerical displacements, the panel deformations and failure modes. By using the validated models, parametric studies can be carried out to optimise the blast resistance of FMLs based on a range of stacking sequences and layer thicknesses
Hearing Reports under the Environmental Conservation Law: Their Function, Preparation, and Importance
Excavation Paperwork of Unit A Levels 8-9 From Penny (8BR158)
This document contains the field notes taken during excavation of test unit A, levels 8-9. It is a scan of original paper documents generated in the field
Metrology and microscopy analysis of multisheet packs manufactured via superplastic forming to study possible diffusion bonding
A number of titanium alloys multisheet packs with predefined complex features were manufactured via superplastic forming (SPF) and investigated via metrology and microscopy analysis to determine the possible occurrence of diffusion bonding. Four sheets of titanium alloys were welded using resistance seam welding based on a defined pattern to manufacture a composite sheet of four layers. Each composite sheet structure was composed of four sheets: two core sheets of the same titanium alloy material - Ti64 or Ti54M, and two external sheets of similar titanium alloy material - Ti64 or Ti6242. The composite sheet structures were inflated via SPF process in pockets where the sheets were not welded to each other to form a complex component. A pressure cycle was determined via the analysis of the numerical data from finite element simulations and a laboratory optimization method to form each multisheet pack. The maximum elongation due to stretching of sheets by SPF could reach 134% of initial part pre-forming. The wall thickness of each inflated packs was measured via GOM scanning all features of the formed structures. The thickness reduction imposed by SPF to the component surfaces was found to be up to 59% at some regions of the packs. Several samples from selected regions of each inflated pack were investigated via scanning electron microscopy (SEM) to study whether diffusion bonding occurred between the sheets. The GOM scanning and image analysis demonstrated that during SPF, the multisheet packs underwent a degree of diffusion bonding where the adjacent sheets exhibited thickness reduction under compression forces
Apparent Activation Energies Associated with Protein Dynamics on Hydrophobic and Hydrophilic Surfaces
AbstractWith the use of single-molecule total internal reflection fluorescence microscopy (TIRFM), the dynamics of bovine serum albumin (BSA) and human fibrinogen (Fg) at low concentrations were observed at the solid-aqueous interface as a function of temperature on hydrophobic trimethylsilane (TMS) and hydrophilic fused silica (FS) surfaces. Multiple dynamic modes and populations were observed and characterized by their surface residence times and squared-displacement distributions (surface diffusion). Characteristic desorption and diffusion rates for each population/mode were generally found to increase with temperature, and apparent activation energies were determined from Arrhenius analyses. The apparent activation energies of desorption and diffusion were typically higher on FS than on TMS surfaces, suggesting that protein desorption and mobility were hindered on hydrophilic surfaces due to favorable protein-surface and solvent-surface interactions. The diffusion of BSA on TMS appeared to be activationless for several populations, whereas diffusion on FS always exhibited an apparent activation energy. All activation energies were small in absolute terms (generally only a few kBT), suggesting that most adsorbed protein molecules are weakly bound and move and desorb readily under ambient conditions
Community Health Workers in Central-Southern Amazonia: An Ethnographic Account of the Munduruku People of KwatĆ” Laranjal Indigenous Land
This article analyzes the role of Munduruku indigenous community health workers (CHW) with the expansion of biomedical services as part of state presence and territorial control in Brazil. Centuries of interethnic contacts among the Munduruku have resulted in a plurality of health practices. Since 1999, Primary services have increased significantly, when the Indigenous Health System (SASI) was created. CHWs were incorporated as part of the health teams serving the indigenous lands. Munduruku CHWs have not only assumed an important role in the delivery of biomedical services, but also are key in the articulation between different traditions of care. Although there is a clash between the hegemony of biomedicine and the Mundurucu cosmographical perspective that links health to territory, the CHWs are protagonists and important actors in the negotiations and appropriations that occur in the contact zone of medical pluralism. They have emerged as local leaders, collaborating with village caciques in health service issues and dialoguing with and supporting families in therapeutic itineraries that include various medical traditions. In addition, they have become political actors in the new participatory spaces created for indigenous representation, such as local and district health councils that are part of the Indigenous Health System
Shovel Test Pit Paperwork of Judgemental Tests from Quarterman (8BR223)
This document contains the field notes taken during phase 1 survey for the judgemental tests
Attentional bias toward negative and positive pictorial stimuli and its relationship with distorted cognitions, empathy, and moral reasoning among men with intellectual disabilities who have committed crimes
The aims of this study were to examine: (a) whether men with intellectual disabilities who have a history of criminal offending attend to affective pictorial stimuli in a biased manner, and (b) whether there is a relationship between an affective attentional bias and offence-supportive cognitions, empathy, and moral development. Forty-six men with intellectual disabilities who had a documented history of criminal offending, and 51 men who also had intellectual disabilities, but no such history, were recruited and asked to complete a computer-based dot-probe task using affective pictorial stimuli with randomisation, along with measures of distorted cognitions, empathy, and moral development. Those with a history of criminal offending endorsed significantly more offence-supportive cognitions, had significantly lower general empathy, and more āmatureā moral development, as well as a significant attentional bias toward affective pictorial stimuli. Attentional bias significantly predicted offence-supportive cognitions, and vice versa, having controlled for offence history, and Full-Scale IQ, but this was not the case for empathy or moral development. While the findings require replication, interventions which aim to modify attention bias with this population should be tested
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Impact of the earthworm Lumbricus terrestris (L.) on As, Cu, Pb and Zn mobility and speciation in contaminated soils
To assess the risks that contaminated soils pose to the environment properly a greater understanding of how soil biota influence the mobility of metal(loid)s in soils is required. Lumbricus terrestris L. were incubated in three soils contaminated with As, Cu, Pb and Zn. The concentration and speciation of metal(loid)s in pore waters and the mobility and partitioning in casts were compared with earthworm-free soil. Generally the concentrations of water extractable metal(loid)s in earthworm casts were greater than in earthworm-free soil. The impact of the earthworms on concentration and speciation in pore waters was soil and metal specific and could be explained either by earthworm induced changes in soil pH or soluble organic carbon. The mobilisation of metal(loid)s in the environment by earthworm activity may allow for leaching or uptake into biota
Long-term effects of nutrient and CO2 enrichment on the temperate coral Astrangia poculata (Ellis and Solander, 1786)
Author Posting. Ā© The Author(s), 2010. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Journal of Experimental Marine Biology and Ecology 386 (2010): 27-33, doi:10.1016/j.jembe.2010.02.007.Zooxanthellate colonies of the scleractinian coral Astrangia poculata were grown
under combinations of ambient and elevated nutrients (5 Ī¼M NO3 -, 0.3 Ī¼M PO4
-3, and 2 nM Fe+2) and CO2 (~780 ppmv) treatments for a period of 6 months. Coral calcification
rates, estimated from buoyant weights, were not significantly affected by moderately
elevated nutrients at ambient CO2 and were negatively affected by elevated CO2 at
ambient nutrient levels. However, calcification by corals reared under elevated
nutrients combined with elevated CO2 was not significantly different from that of corals
reared under ambient conditions, suggesting that CO2 enrichment can lead to nutrient
limitation in zooxanthellate corals. A conceptual model is proposed to explain how
nutrients and CO2 interact to control zooxanthellate coral calcification. Nutrient limited
corals are unable to utilize an increase in dissolved inorganic carbon (DIC) as nutrients
are already limiting growth, thus the effect of elevated CO2 on saturation state drives the
calcification response. Under nutrient replete conditions, corals may have the ability to
utilize more DIC, thus the calcification response to CO2 becomes the product of a
negative effect on saturation state and a positive effect on gross carbon fixation,
depending upon which dominates, the calcification response can be either positive or
negative. This may help explain how the range of coral responses found in different
studies of ocean acidification can be obtained.Funding for this work was provided by the Ocean Life Institute, NSF OCE-0648157, and
an International Society for Reef Studies / Ocean Conservancy Fellowship. This material
is based upon work supported under a National Science Foundation Graduate Research
Fellowship
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