655 research outputs found
Very high temperature silicon on silicon pressure transducers
A silicon on silicon pressure sensor has been developed for use at very high temperatures (1000 F). The design principles used to fabricate the pressure sensor are outlined and results are presented of its high temperature performance
Effect of change in role of an aircraft on engine life
New aircraft require years of development from concept to realisation and can be prone to delays. Consequently, military operators take existing fleets and operate them in a different role. The objective of this study is to examine the effect of operating a typical low bypass military fast jet engine, originally designed for a European theatre, in a hot and harsh climate. The specific purpose is to determine the effect on the high-pressure turbine blade life and the life- cycle cost of the engine.
A mission profile and respective performance conditions were analysed and modelled using an in-house performance tool. The flow conditions were simulated using ANSYS® FLUENT. A conjugated heat transfer solution was adopted to determine the blade metal temperature. The blade was modelled physically in 3D using SIMULIA® ABAQUS FEA software. The stresses were derived and used to calculate the temperature coupled low cycle fatigue and creep life.
A deterioration case was also studied to evaluate the effect of sand and dust ingestion. There was a significant life reduction of approximately 50% due to creep. The reduction in life was inversely proportional to the life cycle cost of the engine depending on the operating conditions. The results were compared with similar engines and summarised in the context of airworthiness regulations and component integrity
Bison foraging responds to fire frequency in nutritionally heterogeneous grassland
Citation: Raynor, E. J., Joern, A., & Briggs, J. M. (2015). Bison foraging responds to fire frequency in nutritionally heterogeneous grassland. Ecology, 96(6), 1586-1597. doi:10.1890/14-2027.1Foraging decisions by native grazers in fire-dependent landscapes modulate the fire-grazing interaction. Uncovering the behavioral mechanisms associated with the attraction of grazers to recently burned areas requires understanding at multiple spatial scales in the ecological foraging hierarchy. This study focused on feeding in the area between steps in a foraging bout, the feeding station, as forage chemistry and vegetation architecture play central roles in these fine-scale, feeding-station decisions. The forage maturation hypothesis (FMH) uses the temporal dynamics of forage quality and quantity in grasslands to explain the distribution of large herbivores, but does not address herbivore responses to inter-patch variation caused by fire-induced nutrient increases of forage quality. Using an experimental setting with contrasting fire treatments we describe the effects of variable burn history on foraging kinetics by bison at Konza Prairie Biological Station (KPBS). We assessed the potential to link the FMH in a complementary fashion to the transient maxima hypothesis (TMH) to explain temporal variation in bison responses to grassland forage quality and quantity in response to burning at different temporal frequencies. Forage attributes met predictions of the TMH that allowed us to investigate how forage maturation affects feeding station foraging behavior across watersheds with varying burn frequency. At sites burned in the spring after several years without burning, both bite mass and intake rate increased with increasing biomass at a greater rate during the growing season than during the transitional midsummer seasonal period. In these infrequently burned watersheds, early growing season bite mass (0.6 +/- 0.05 g; mean +/- SE), bite rate (38 +/- 1.5 bites/ min), and intake rate (21 +/- 2.3 g/min) was reduced by similar to 15%, 13%, and 29% during the midsummer transitional period. A behavioral response in foraging kinetics at the feeding station occurred where a nonequilibrial pulse of high-quality resource was made available and then retained by repeated grazing over the growing season. Our results provide the first experimental evidence for demonstrating the fine-scale behavioral response of a large grazer to fire-induced changes in forage attributes, while linking two prominent hypotheses proposed to explain spatial variation in forage quality and quantity at local and landscape scales
Studies for improved vapour-liquid contacting
The object of the work was to attempt to propose an improvement in the process of vapour-liquid contacting with particular reference to commercial distillation.
The literature was reviewed by considering both the overall performance data of the methods and devices used for contacting and the more fundamental studies of the mechanisms and effects taking place in them. It was concluded that the cross-flow Sieve tray with a high free area and many small holes would offer the best performance. This solution, however, is not commercially viable as the cost of producing a device to these specifications by conventional means would be excessive. To overcome this economic restraint and to retain the improved performance, a cheaper method of tray floor construction was proposed in which the material used was inherently porous.
Many materials satisfy the requirements for use as a tray floor, for example, open cloths, meshes and gauzes and open cell foam and sintered materials. Sorting tests were, therefore, performed on a small scale, using an air-water system, to eliminate those materials which gave unsatisfactory hydraulic performance. A 68" x 14" column, also using an air-water system, was employed to test the feasibility and the hydraulic performance of the proposed tray floors on a large scale. The same apparatus was then used to determine the liquid mixing characteristics of the most promising material.
To discover the performance of the new trays under actual vapour-liquid conditions, a 12” diameter, three tray distillation column was built and used experimentally. The separation efficiencies and tray pressure drops were evaluated for total reflux conditions at various vapour rates and outlet weir heights using the systems toluene n-heptane and toluene methyl-cyclo-hexane. The results for the new glass cloth trays showed that better performance could be obtained than conventional trays, particularly with regard to the flexibility.
Various interesting phenomena manifested themselves in marked differences between the results obtained for the same material using the air-water and the hydrocarbon systems. The factors and their effects which produce these phenomena were, therefore, studied using various systems and glass cloths in a 3" diameter column
Embedding Interprofessional Activities with Physical Therapy and Athletic Training Students in Shared Professional Course
Introduction and Background: Interprofessional education (IPE) is outlined in many health professions education standards creating an increased demand for its inclusion in already crowded curricula with limited faculty and financial resources. The Interprofessional Education Collaborative (IPEC) developed “Core Competencies for Interprofessional Collaborative Practice” that outline a framework for meaningful IPE experiences. Case-based learning activities have been used to foster improvements in interprofessional role clarity, communication, and rapport among student groups. The authors describe one trial of incorporating interprofessional and team work activities in a shared professional course and report on student learning outcomes in the context of IPEC competencies.
Course Design: In an existing shared professional course, athletic training (AT) and physical therapy (PT) students were exposed to an interprofessional teaching team and engaged in team work activities during lab sessions. Students were also assigned to interprofessional (IP) and uniprofessional (UP) teams to complete four case-based learning activities regarding the application of therapeutic modalities in various patient cases. Students then wrote critical reflections of their experiences working in teams. Instructors evaluated these reflections in the context of eight relevant IPEC sub-competencies.
Outcomes: Both IP and UP groups of students were able to articulate the demonstration of each of the eight IPEC sub-competencies, suggesting that incorporating a variety of interprofessional and team work activities in a shared professional course may offer a valuable IPE experience that promotes development of students’ collaboration skills.
Discussion and Conclusion: Embedding IPE in existing curricula could be a viable way to overcome many of the challenges faced by health professions programs, meet IPE accreditation standards, and prepare students for interprofessional collaborative practice
Interprofessional Role Clarity, Case-Based Learning, and Perceptions of Group Effectiveness Among Athletic Training and Physical Therapy Students in a Shared Professional Course
Purpose: Health professions students experience professional socialization during their program of study. Institutions have turned to interprofessional education as a means of preparing students for their role as collaborative health care professionals. This study examines the effect of case-based learning experiences in a shared professional Therapeutic Modalities course on student’s interprofessional role clarity as well as the relationship between interprofessional role clarity and measure of group effectiveness. Methods: 112 students (22 Athletic Training and 90 Physical Therapy) were assigned to one of 18 interprofessional and 18 uniprofessional teams and asked to complete four case-based learning activities. All students completed pre-test, retrospective pre-test, and post-test role clarity/ambiguity scales. Measures of team viability, team member satisfaction, and self-rated output were collected post-intervention. Results: Results suggest the experience of interacting with one another in this course, including during case-based learning activities, may lead to increased knowledge of other’s roles and responsibilities as shown in the retrospective pre-test and post-test role clarity differences. Additionally, role clarity has meaningful relationships with measures of perceived group effectiveness, particularly team viability and self-rated output. Conclusion: We suggest that health professions educators consider incorporating case-based learning activities into existing curricula to introduce other professions’ roles and engage students in teamwork
For the Greater Good: Sacrificial Violence and the Coronavirus Pandemic
The Covid-19 pandemic has ushered in an unprecedented epoch of myriad sacrifice. Unseen since World War Two, restrictions have been placed upon our movement at various degrees of intensity since March 2020. Across the world, citizenries have been informed by states to transiently sacrifice their cultural freedoms to protect the sacred – namely, healthcare systems and thereby help to preserve life, particularly the elderly. However, so far, little scholarly attention has been awarded to the presence of sacrifice throughout the pandemic. Therefore, this article is structured into four core themes. Whilst the first section outlines the moral and ethical quandaries generated by the Covid-19 pandemic, the second section explores the theoretical work on violence, since contemporary sacrifice is intimately connected to the systemic violence inherent in neoliberal capitalist economies. Next, the paper explicates the role of sacrifice during the pandemic, particularly through the sacrifices made by ‘key workers’ like care workers and nurses, outlining how neoliberalism’s systemic violence meant they were met with tokenistic gestures including clapping rather than a fundamental improvement in their working conditions. As sacrifice has historically served to reinforce the social fabric, the article closes with a discussion on whether sacrifice during the pandemic is likely to achieve this, given neoliberalism’s primacy to post-social arrangements including radical individualism, emotivism, and competition
Critical Reflections on the COVID-19 Pandemic from the NHS Frontline
The COVID-19 pandemic fundamentally changed the way we live, work, and interact with each other. Nowhere was the pandemic more profoundly experienced than on the frontline of healthcare. From overwhelmed Intensive Care Units to shortages of Personal Protective Equipment (PPE) and clap for carers, the UK’s National Health Service (NHS) became the focal point for the pandemic response. Utilising data from online survey responses (N = 16) complemented by four online interviews and one face-to-face interview (N = 5) with NHS workers primarily during the height of the pandemic, this article offers a preliminary analysis on the challenges the UK’s healthcare workers faced through working in conditions of crisis management. The article particularly addresses NHS workers’ amplification of fear, anxiety, and exhaustion; the absence of widespread solidarity; and implications of the absence of coherent governmental messaging upon the workforce. We situate this discussion within a critical account of neoliberal political economy, the theoretical framework of social harm, and the absence to explicate the harmful conditions of the pandemic’s frontline. While the data are confined to the UK’s NHS workers, its findings are relevant to other countries across the world that enacted similar responses to deal with COVID-19.Sin financiación1.315 Q3 JCR 20210.509 Q2 SJR 2022No data IDR 2021UE
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