Effect of oil contaminated aggregates on cement hydration

Canola oil, refined mineral oil, and crude oil additions up to 10% of the aggregate mass in Portland cement mortars were found to decrease the 28-day compressive strength by 71%, 75% and 50%, respectively, and retard setting times. There was a progressive impact upon cement hydration as the oil content increased in mortars. Only in the case of vegetable oil and refined mineral oil could strength loss be attributed in part to cement hydration inhibition, as evidenced by reduced total evolved heat. It is likely that microstructural effects were also a key factor in strength loss for all mortars particularly for those containing crude oil

Composite Overwrapped Pressure Vessels, A Primer

Due to the extensive amount of detailed information that has been published on composite overwrapped pressure vessels (COPVs), this document has been written to serve as a primer for those who desire an elementary knowledge of COPVs and the factors affecting composite safety. In this application, the word "composite" simply refers to a matrix of continuous fibers contained within a resin and wrapped over a pressure barrier to form a vessel for gas or liquid containment. COPVs are currently used at NASA to contain high pressure fluids in propulsion, science experiments, and life support applications. They have a significant weight advantage over all metal vessels but require unique design, manufacturing, and test requirements. COPVs also involve a much more complex mechanical understanding due to the interplay between the composite overwrap and the inner liner. A metallic liner is typically used in a COPV as a fluid permeation barrier. The liner design concepts and requirements have been borrowed from all-metal vessels. However, application of metallic vessel design standards to a very thin liner is not straightforward. Different failure modes exist for COPVs than for all-metal vessels, and understanding of these failure modes is at a much more rudimentary level than for metal vessels

The occurrence of cardiac abnormalities in canine steroid‐responsive meningitis arteritis

Objectives: To document the prevalence of cardiac abnormalities in dogs with steroid‐responsive meningitis arteritis and to assess resolution of these abnormalities following corticosteroid therapy. Materials and Methods: Steroid‐responsive meningitis arteritis was diagnosed based on signalment, physical examination findings, complete blood count, biochemistry and CSF analysis. Echocardiography, C‐reactive protein and cardiac troponin I were measured in all cases before and 10 to 14 days after commencing corticosteroid therapy. Fibrinogen was also measured in a proportion of dogs. Results: Fourteen dogs were prospectively enrolled. Increased cardiac troponin I was identified in five of 14 dogs and echocardiographic abnormalities were detected in 12 of 14 dogs, including spontaneous echo contrast (12 of 14), mild pericardial effusion (five of 14) and mildly decreased fractional shortening (five of 14). All dogs had increased C‐reactive protein and fibrinogen was increased in 11 of 12. Corticosteroid treatment was associated with clinical improvement and normalisation of C‐reactive protein in all dogs. The cardiac troponin I levels normalised in four of five and fibrinogen had normalised in all five dogs which were retested. Spontaneous echo contrast improved or completely resolved in 12 of 12 and pericardial effusion resolved in five of five dogs. Fractional shortening normalised in two of five dogs. Clinical Significance: Cardiac changes are common in dogs with steroid‐responsive meningitis arteritis and most resolve with therapy. Further investigation into the cause and significance of these changes is necessary in determining whether antithrombotic therapy or positive inotropic therapy is indicated

Spin-orbit splitting of image states

We quantify the effect of the spin-orbit interaction on the Rydberg-like series of image state electrons at the (111) and (001) surface of Ir, Pt and Au. Using relativistic multiple-scattering methods we find Rashba-like dispersions with Delta E(K)=gamma K with values of gamma for n=1 states in the range 38-88 meV Angstrom. Extending the phase-accumulation model to include spin-orbit scattering we find that the splittings vary like 1/(n+a)^3 where a is the quantum defect and that they are related to the probability of spin-flip scattering at the surface. The splittings should be observable experimentally being larger in magnitude than some exchange-splittings that have been resolved by inverse photoemission, and are comparable to linewidths from inelastic lifetimes.Comment: 10 pages, 4 figure

Deep learning for real-time multi-class segmentation of artefacts in lung ultrasound

Lung ultrasound (LUS) has emerged as a safe and cost-effective modality for assessing lung health, particularly during the COVID-19 pandemic. However, interpreting LUS images remains challenging due to its reliance on artefacts, leading to operator variability and limiting its practical uptake. To address this, we propose a deep learning pipeline for multi-class segmentation of objects (ribs, pleural line) and artefacts (A-lines, B-lines, B-line confluence) in ultrasound images of a lung training phantom. Lightweight models achieved a mean Dice Similarity Coefficient (DSC) of 0.74, requiring fewer than 500 training images. Applying this method in real-time, at up to 33.4 frames per second in inference, allows enhanced visualisation of these features in LUS images. This could be useful in providing LUS training and helping to address the skill gap. Moreover, the segmentation masks obtained from this model enable the development of explainable measures of disease severity, which have the potential to assist in the triage and management of patients. We suggest one such semi-quantitative measure called the B-line Artefact Score, which is related to the percentage of an intercostal space occupied by B-lines and in turn may be associated with the severity of a number of lung conditions. Moreover, we show how transfer learning could be used to train models for small datasets of clinical LUS images, identifying pathologies such as simple pleural effusions and lung consolidation with DSC values of 0.48 and 0.32 respectively. Finally, we demonstrate how such DL models could be translated into clinical practice, implementing the phantom model alongside a portable point-of-care ultrasound system, facilitating bedside assessment and improving the accessibility of LUS

Developing scholarship through collaboration in an online roleplay-simulation: Mekong eSim, a case study

Mekong e-Sim was designed to create an authentic learning environment in which students from different disciplines work together to learn about the complexities of environmental decision-making. The version of Mekong e-Sim that is reported here involved students of the subjects Asia-Pacific Development (geography), Technology Assessment (technological developments and impacts in engineering) and Environmental Engineering. During the Mekong e-Sim, students collaborated to adopt different stakeholder roles and initiate and respond to major events relating to economic and environmental development in the Mekong region. Key tasks included responding to topical news events, making submissions to public planning inquiries, writing reports and debating development issues in the Mekong region. Through their participation in Mekong e-Sim, students developed understanding of the complexities of decision-making, appreciation of the range of perspectives associated with environmental management and developed subject specific skills and understandings. A description of the design and evaluation of the Mekong e-Sim is provided in McLaughlan et al. (2001). The development of the teaching project was a collaborative, cross-institutional teaching development that brought together staff with a range of skills and expertise. Despite the fact that there has been increasing attention to scholarly values in universities in recent years there has been little consideration of what this might look like. This paper uses the case of the development and teaching of Mekong e-Sim to investigate scholarly teaching, particularly the process and practice of scholarship and teaching in a team situation

Using Online Roleplay/Simulations for Creating Learning Experiences

Over 140 geography and engineering students from across Australia and overseas spent 4 weeks participating in an online roleplay-simulation set in the Mekong region of South East Asia. The online environment provides a setting for the construction of alternative points of view and a lively debate and creates an authentic context for student collaboration. The roleplay-simulation involves decision-making and conflict resolution regarding natural resource development. The Mekong e-Sim (electronic simulation) has been designed to support the learning of students studying subjects in the subjects Technology Assessment, Environmental Engineering or Asia Pacific Development Studies at different universities. The students share the online roleplay simulation experience, which is then utilised differently within each of the geography or engineering subjects at the institution where the students are enrolled. Student and staff response has been very positive. Students report that the e-Sim provides a realistic experience, is engaging, develops their information technology and communication skills and increases their awareness of multiple perspectives on the issues involved