Direct observation of oil consumption mechanisms in a production spark ignition engine using fluorescence techniques

The oil consumption characteristics of a four cylinder, normally aspirated spark-ignition engine were investigated for different piston ring end-gap configurations. A radiotracer was used to perform direct measurement of the oil consumption while Laser-induced Fluorescence (LIF) was used to perform the oil film thickness measurements for consumption predictions using the "Puddle Theory of Oil Consumption, " which relates oil consumption to second land film thickness and reverse flow through top ring gap. The consumption data was evaluated to determine the impact of top ring end-gap azimuthal location on oil consumption. The film thickness data was used to evaluate the extent to which the Oil Puddle Theory predicts variations seen in the actual oil consumption. A tritium radiotracer oil consumption measurement system with an accuracy of 94.6% was designed and constructed. This was used to perform direct measurements of the test engine oil consumption in two different test matrices. The first evaluated a piston ring configuration with the rings free to rotate. The second evaluated configurations with the top ring and second piston rings pinned to fix the azimuthal location of the end-gap; the azimuth of the top ring was varied. In the second test matrix, the oil film thickness on the piston's second land was measured, and predictions were made on the basis of that measurement . The first test matrix results indicated only a weak speed dependence and a large amount of variability in the oil consumption measurements. The second test matrix results showed an oil consumption speed dependence that was a function of top gap azimuth. Speed normalized results showed that the oil consumption was larger when the end-gap was on the thrust side of the test engine than when on the anti-thrust side. Measured oil consumption differed substantially from that predicted. This was found to be due to difficulties in determining effective ring gap flow areas and due to a previously un-documented azimuthal variation in second land oil film thickness. However, analysis of the results also indicates that the Puddle Theory is still a plausible oil consumption mechanism.http://archive.org/details/directobservatio00lus

Direct observation of oil consumption mechanisms in a production spark ignition engine using fluorenscence techniques

Thesis (Nav. E.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1994, and Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1994.Includes bibliographical references (leaves 114-115).by Roderick M. Lusted.M.S.Nav.E

Evaluation Method, Dataset Size or Dataset Content: How to Evaluate Algorithms for Image Matching?

Most vision papers have to include some evaluation work in order to demonstrate that the algorithm proposed is an improvement on existing ones. Generally, these evaluation results are presented in tabular or graphical forms. Neither of these is ideal because there is no indication as to whether any performance differences are statistically significant. Moreover, the size and nature of the dataset used for evaluation will obviously have a bearing on the results, and neither of these factors are usually discussed. This paper evaluates the effectiveness of commonly used performance characterization metrics for image feature detection and description for matching problems and explores the use of statistical tests such as McNemar’s test and ANOVA as better alternatives

‘Race’ Talk! Tensions and Contradictions in Sport and PE

Background: The universal sport discourses of inclusion, belonging, meritocracy, agency, and equality are so widespread that few challenge them. It is clear from the most cursory interest in sport, PE and society that the lived reality is quite different and ambiguous. Racial disparities in the leadership and administration of sport are commonplace world wide; yet from research into ‘race’ in sport and PE the public awareness of these issues is widespread, where many know that racism takes place it is always elsewhere For many this racism is part of the game and something that enables an advantage to be stolen, for others it is trivial and not worthy of deeper thought. This paper explores the contradictions and tensions of the author’s experience of how sport and PE students talk about ‘race’. ‘Race’ talk is considered here in the context of passive everyday ‘race’ talk, dominant discourses in sporting cultures, and colour-blindness. This paper focuses on the pernicious yet persistent nature of ‘race’ talk while demystifying its multifarious, spurious, and more persuasive daily iterations. Theoretical framework: Drawing on Guinier and Torres’ (2003) ideas of resistance through political race consciousness and Bonilla-Silva’s (2010) notion of colour-blindness the semantics of ‘race’ and racialisation in sport and PE are interrogated through the prism of Critical Race Theory (CRT). Critical race scholarship has been used in sport and PE to articulate a political application of ‘race’ as a starting point for critical activism, to disrupt whiteness, and to explore the implications of ‘race’ and racism. CRT is used here to centre ‘race’ and racialised relations where disciplines have consciously or otherwise excluded them. Importantly, the centreing of ‘race’ by critical race scholars has advanced a strategic and pragmatic engagement with this slippery concept that recognises its paradoxical but symbolic location in social relations. Discussion: Before exploring ‘race’ talk in the classroom, using images from the sport media as a pedagogical tool, the paper considers how effortlessly ‘race’ is recreated and renewed. The paper then turns to explore how the effortless turn to everyday ‘race’ talk in the classroom can be viewed as an opportunity to disrupt common racialised assumptions with the potential to implicate those that passively engage in it. Further the diagnostic, aspirational and activist goals of political race consciousness are established as vehicles for a positive sociological experience in the classroom. Conclusion: The work concludes with a pragmatic consideration of the uses and dangers of passive everyday ‘race’ talk and the value of a political race consciousness in sport and PE. Part of the explanation for the perpetuation of ‘race’ talk and the relative lack of concern with its impact in education and wider society is focused on how the sovereignty of sport and PE trumps wider social concerns of ‘race’ and racism because of at least four factors 1) the liberal left discourses of sporting utopianism 2) the ‘race’ logic that pervades sport, based upon the perceived equal access and fairness of sport as it coalesces with the, 3) 'incontrovertible facts' of black and white superiority [and inferiority] in certain sports, ergo the racial justifications for patterns of activity in sport and PE 4) the racist logic of the Right perpetuated through a biological reductionism in sport and PE discourses. Keywords: ‘Race’ Talk; Critical Race Theory; Political Race Consciousnes

The influence of medical expertise, case typicality and illness script component on case processing and disease probability estimates

The present study investigated the influence of medical expertise, case typicality, and illness script component (enabling conditions vs. consequences) on the speed of case informati

The doctoral studies paradox: Indigenous cultural paradigms versus Western-based research practices

This is an exploratory conceptual paper regarding the ontological and epistemological premises that are present in the enrollment of Indigenous peoples in doctoral programs at higher education institutions (HEIs). The paradoxical nature of navigating through distinct points-of-view about two distinct cultural perspectives, that of the doctorate representing a culminating recognition of a professional culture based on Western tradition and the norms and values of Indigenous cultures. There are personal risks involved in undergoing an education predicated on conflicting messages paradoxes represent from prior personal and collective experience and from institutional dicta and expectations. This paper looks at how an individual brings these elements together in a transformative manner that accepts or rejects governmental preference for enhanced participation by Indigenous peoples in doctoral education programs