2,111 research outputs found
Effects of closed immersion filtered water flow velocity on the ablation threshold of bisphenol A polycarbonate during excimer laser machining
A closed flowing thick film filtered water immersion technique ensures a controlled geometry for both the optical interfaces of the flowing liquid film and allows repeatable control of flow-rate during machining. This has the action of preventing splashing, ensures repeatable machining conditions and allows control of liquid flow velocity. To investigate the impact of this technique on ablation threshold, bisphenol A polycarbonate samples have been machined using KrF excimer laser radiation passing through a medium of filtered water flowing at a number of flow velocities, that are controllable by modifying the liquid flow rates. An average decrease in ablation threshold of 7.5% when using turbulent flow velocity regime closed thick film filtered water immersed ablation, compared to ablation using a similar beam in ambient air; however, the use of laminar flow velocities resulted in negligible differences between closed flowing thick film filtered water immersion and ambient air. Plotting the recorded threshold fluence achieved with varying flow velocity showed that an optimum flow velocity of 3.00 m/s existed which yeilded a minimum ablation threshold of 112 mJ/cm2. This is attributed to the distortion of the ablation plume effected by the flowing immersion fluid changing the ablation mechanism: at laminar flow velocities Bremsstrahlung attenuation decreases etch rate, at excessive flow velocities the plume is completely destroyed, removing the effect of plume etching. Laminar flow velocity regime ablation is limited by slow removal of debris causing a non-linear etch rate over ânâ pulses which is a result of debris produced by one pulse remaining suspended over the feature for the next pulse. The impact of closed thick film filtered water immersed ablation is dependant upon beam fluence: high fluence beams achieved greater etch efficiency at high flow velocities as the effect of Bremsstrahlung attenuation is removed by the action of the fluid on the plume; low fluences loose efficiency as the beam makes proportionally large fluence losses at it passes through the chamber window and immersion medium
Exploring racial bias in a European country with a recent history of immigration of black Africans
Response biases on the IRAP for adults and adolescents with respect to smokers and nonsmokers : the impact of parental smoking status
Exploring the potential impact of relational coherence on persistent rule-following : the first study
Rule-governed behavior and derived relational responding have both been identified as important variables in human learning. Recent developments in the relational frame theory (RFT) have outlined a number of key variables of potential importance when analyzing the dynamics involved in derived relational responding. Recent research has explored the impact of one of these variables, level of derivation, on persistent rule-following and implicated another, coherence, as possibly important. However, no research to date has examined the impact of coherence on persistent rule-following directly. Across two experiments, coherence was manipulated through the systematic use of performance feedback, and its impact was examined on persistent rule-following. A training procedure based on the implicit relational assessment procedure (IRAP) was used to establish novel combinatorially entailed relations that manipulated the feedback provided on the trained relations (A-B and B-C) in Experiment 1, and on the untrained, derived relations (A-C) in Experiment 2. One of these relations was then inserted into the rule for responding on a subsequent contingency-switching match-to-sample (MTS) task to assess rule persistence. While no significant differences were found in Experiment 1, the provision or non-provision of feedback had a significant differential impact on rule-persistence in Experiment 2. Specifically, participants in the Feedback group resurged back to the original rule for significantly more responses after demonstrating contingency-sensitive responding than did the No-Feedback group, after the contingency reversal. The results highlight the subtle complexities that appear to be involved in persistent rule-following in the face of reversed reinforcement contingencies
"Do you want fries with that?": the McDonaldization of university education â some critical reflections on nursing higher education
Public universities, as the predominant source of nurse education, serve an instrumental role as pressure mounts to produce large numbers of workready graduates to meet the needs of the labor market. Neoliberalism is recognized as the dominant political and economic philosophy across the globe, and new managerialist, corporatized practices, as its âorganizational arms,â are ubiquitous within the higher education sector worldwide. Intersecting this agenda are dramatic developments in the way university courses are being conceived and delivered based upon the increasing integration of digital technologies. Given the radical transformations brought about by Web 2.0 technologies, it is timely to critically analyze current narratives shaping the teaching and learning agenda and their impact on the nature and quality of nursing higher education. This article draws on the âMcDonaldization thesisâ of George Ritzer, concepts from the work of the Italian philosopher Giorgio Agamben, Habermasian social theory, and critical pedagogy. It concludes with a short overview of possible outcomes of the new agenda, and some strategies for resistance. Although the focus is on Australia, it is relevant to other countries to the extent that they are facing similar challenges and undergoing analogous pedagogic transformations
In search of Christian theological research methodology
The burgeoning methodological literature available for the guidance of researchers caters for a wide range of standpoints, but it ignores perhaps the commonest personal philosophies encountered in the nursing profession, those based on Christianity. Nursingâs historical and continuing relationship to Christian faith has been well-documented, and although this is reflected in literature stressing the importance of spiritual care, it has had no discernible impact on nursesâ formulations of research methodology. This article outlines the core features of Christian belief and draws out some of their methodological implications for nurse researchers, with a view to initiating a constructive debate from which Christian theological methodologies might be developed
The Status of Rule-Governed Behavior as Pliance, Tracking and Augmenting within Relational Frame Theory: Middle-Level Rather than Technical Terms
A recent systematic review has highlighted that the terms âpliance,â âtracking,â and âaugmentingâ have rarely been used as the basis for conducting systematic experimental-analytic research since their conception in 1982, despite their theoretical centrality to the study of rule-governed behavior and their presumed impact on psychological suffering. Given that some time has passed since the review article, it may be useful to reflect again upon their place within the literature on the experimental analysis of human behavior, and relational frame theory in particular. As such, the current article constitutes a âposition pieceâ rather than another formal systematic review. In reviewing (informally) the literature since the systematic review, the recent emergence of psychometric research involving these concepts could be seen as reinforcing the original conclusions, in that researchers are recognizing that pliance, tracking, and augmenting may be of limited value in the experimental analysis of human behavior. Instead, the concept of rule-governed behavior itself, as well as the subcategories of pliance, tracking, and augmenting, should be considered middle-level terms, which lack the relative precision of more technical terms within the literature on relational frame theory
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