1,006 research outputs found

    Ignition of metals in high pressure oxygen

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    A description of an experimental facility used to determine the ignition and combustion characteristics of metallic materials is given. The results obtained for aluminum 6061, 302 stainless steel, and the nickel alloy - N06625 are presented

    Laser-initiated combustion studies of selected aluminum, copper, iron, and nickel alloys

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    The results of combustion studies at atmospheric pressure on ten metal alloys are presented. The alloys studied were aluminum alloys 1100, 2219, 6061, and tensile-50; 304, 347 and 21-6-9 stainless steel; inconel 600; beryllium copper and a bronze. It was found that once ignition was achieved all alloys would generally burn to completion. The overall combustion process appears to obey a first order rate process. Preliminary conclusions are presented along with recommendations for future work

    Ignition characteristics of the nickel-based alloy UNS N07001 in pressurized oxygen

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    The development of ignition and combustion in pressurized oxygen atmospheres was studied for the nickel-based alloy UNS N07001. Ignition of the alloy was achieved by heating the top surface of a cylindrical specimen with a continuous-wave CO2 laser. Two heating procedures were used. In the first, laser power was adjusted to maintain an approximately linear increase in surface temperature. In the second, laser power was periodically increased until autoheating (self-heating) was established. It was found that the alloy would autoheat to combustion from temperatures below the solidus temperature. In addition, the alloy had a tendency to develop combustion zones (hot spots) at high oxygen pressures when the incremental (step) heating test mode was used. Unique points on the temperature-time curves that describe certain events are defined and the temperatures at which these events occur are given for the oxygen pressure range of 1.72 to 13.8 MPa (250 to 2000 psia)

    Flammability study of materials in oxygen environments

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    Report presents flame-propagation rates and flammability ratings of 780 specimens of commercially available plastics, elastomers, coatings, fabrics, and other sheet materials. Test results are also given for over 1970 samples of most commonly used electrical harnesses, connectors, and potting compounds

    LOX/GOX mechanical impact tester assessment

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    The performances of three existing high pressure oxygen mechanical impact test systems were tested at two different test sites. The systems from one test site were fabricated from the same design drawing, whereas the system tested at the other site was of different design. Energy delivered to the test sample for each test system was evaluated and compared. Results were compared to the reaction rates obtained

    Conceptual learning : the priority for higher education

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    The common sense notion of learning as the all-pervasive acquisition of new behaviour and knowledge, made vivid by experience, is an incomplete characterisation, because it assumes that the learning of behaviour and the learning of knowledge are indistinguishable, and that acquisition constitutes learning without reference to transfer. A psychological level of analysis is used to argue that conceptual learning should have priority in higher education

    Religious Education, Big Ideas and the study of religion(s) and worldview(s)

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    This is the author accepted manuscript. The final version is available from Taylor & Francis (Routledge) via the DOI in this record.This article outlines the ‘Big Ideas’ approach to curriculum reform, as applied in the ‘Principles and Big Ideas of Science Education’ project (Harlen 2010). A critical analysis follows of the outcomes of the University of Exeter’s ‘Identifying Principles and Big Ideas for Religious Education’ project, which sought to apply the same approach to Religious Education (RE) in English schools (Wintersgill 2017). This project made great headway in generating ‘Big Ideas’ to inform and improve the selection and sequencing of RE curriculum content. However, its primary focus on subject content knowledge mean that ‘Big Ideas’ about epistemology and methodology are lacking. The article recommends an additional focus on multi-disciplinary, multi-methodological, inquiry-based, reflexive learning, which would ask why, how, where and by whom our ‘knowledge’ of religion(s) and worldview(s) is generated. In this regard, the article posits four ‘Big Ideas about the study of religion(s) and worldview(s)’ to highlight the symbiotic relationship between knowledge and knower, and to reject the false dichotomy between the object of study and method of study. In so doing, it draws upon the theoretical framework underpinning the ‘RE-searchers approach’ to primary school RE, which correspondingly exemplifies how such ideas can be taught in practice.The ‘Identifying Principles and Big Ideas for Religious Education’ project was supported by the St Luke’s College Foundation (016J-086). The ‘RE-searchers: A critical dialogic approach to Religious Education in primary schools’ project was supported by the Culham St. Gabriel’s Trust and Hockerill Education Foundation

    Spinal involvement in mucopolysaccharidosis IVA (Morquio-Brailsford or Morquio A syndrome): presentation, diagnosis and management.

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    Mucopolysaccharidosis IVA (MPS IVA), also known as Morquio-Brailsford or Morquio A syndrome, is a lysosomal storage disorder caused by a deficiency of the enzyme N-acetyl-galactosamine-6-sulphate sulphatase (GALNS). MPS IVA is multisystemic but manifests primarily as a progressive skeletal dysplasia. Spinal involvement is a major cause of morbidity and mortality in MPS IVA. Early diagnosis and timely treatment of problems involving the spine are critical in preventing or arresting neurological deterioration and loss of function. This review details the spinal manifestations of MPS IVA and describes the tools used to diagnose and monitor spinal involvement. The relative utility of radiography, computed tomography (CT) and magnetic resonance imaging (MRI) for the evaluation of cervical spine instability, stenosis, and cord compression is discussed. Surgical interventions, anaesthetic considerations, and the use of neurophysiological monitoring during procedures performed under general anaesthesia are reviewed. Recommendations for regular radiological imaging and neurologic assessments are presented, and the need for a more standardized approach for evaluating and managing spinal involvement in MPS IVA is addressed

    The effect of professional development on elementary science teachers’ understanding, confidence, and classroom implementation of reform‐based science instruction

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    Through a randomized controlled trial, this mixed‐methods study evaluated changes in elementary science teachers’ understandings, confidence, and classroom implementation of problem‐based learning (PBL), inquiry, and nature of science (NOS) instruction following participation in a professional development (PD) as well as the components of the PD that teachers perceived facilitated these changes. Results indicated that following the PD, treatment teacher (n = 139) understandings of and confidence for teaching inquiry, NOS, and PBL were significantly greater than control teachers (n = 98) after controlling for preunderstandings and confidence. The effect sizes were large. Treatment teachers also incorporated significantly more PBL, inquiry, and NOS into their instruction. Modeling, microteaching with feedback and reflection, and in‐classroom coaching facilitated teachers’ confidence, understanding, and intention to implement the reform‐based practices they learned. Implications for the understanding of the relationship between knowledge, confidence, and practice as well as elementary science teacher PD design are discussed