Near-Wall Turbulent Pressure Diffusion Modeling and Influence in Three-Dimensional Secondary Flows

The purpose of this paper is to develop a second-moment closure with a near-wall turbulent pressure diffusion model for three-dimensional complex flows, and to evaluate the influence of the turbulent diffusion term on the prediction of detached and secondary flows. A complete turbulent diffusion model including a near-wall turbulent pressure diffusion closure for the slow part was developed based on the tensorial form of Lumley and included in a re-calibrated wall-normal-free Reynolds-stress model developed by Gerolymos and Vallet. The proposed model was validated against several one-, two, and three-dimensional complex flows.

Open design of high pressure ratio radial-inflow turbine for academic validation

Computational Fluid Dynamics (CFD) simulations are widely used in mechanical engineering. Although achieving a high level of confidence in numerical modelling is of crucial importance in the field of turbomachinery, verification and validation of CFD simulations are very tricky especially for complex flows encountered in radial turbines. Comprehensive studies of radial machines are available in the literature. Unfortunately, none of them include enough detailed geometric data to be properly reproduced and so cannot be considered for academic research and validation purposes. As a consequence, design improvements of such configurations are difficult. Moreover, it seems that well-developed analyses of radial turbines are used in commercial software but are not available in the open literature especially at high pressure ratios. It is the purpose of this paper to provide a fully open set of data to reproduce the exact geometry of the high pressure ratio single stage radial-inflow turbine used in the Sundstrand Power Systems T-100 Multipurpose Small Power Unit. First, preliminary one-dimensional meanline design and analysis are performed using the commercial software RITAL from Concepts-NREC in order to establish a complete reference test case available for turbomachinery code validation. The proposed design of the existing turbine is then carefully and successfully checked against the geometrical and experimental data partially published in the literature. Then, three-dimensional Reynolds-Averaged Navier-Stokes simulations are conducted by means of the Axcent-PushButton CFDR CFD software. The effect of the tip clearance gap is investigated in detail for a wide range of operating conditions. The results confirm that the 3D geometry is correctly reproduced. It also reveals that the turbine is shocked while designed to give a high-subsonic flow and highlight the importance of the diffuser.

Threshold concepts in property education : a case study

First year Property Economics students enrolled in the Bachelor of Urban Development at QUT are required to undertake a number of compulsory subjects, alongside students undertaking studies in other disciplines. One such common unit is ‘Stewardship of Land’, an interdisciplinary unit that introduces students to the characteristics of land and land tenure with a focus on land use and property rights. It covers a range of issues including: native title, land contamination, heritage values, alternative uses, the property development process, impact of environmental and social factors, and the management of land, both urban and regional. Teaching such a diverse content to a diverse audience has in previous years proved difficult, from the perspectives of relevance, engagement and content overload. In 2011 a project was undertake to redevelop this unit to reflect ‘threshold concepts’, concepts that are “transformative, probably irreversible, integrative, often troublesome and probably bounded” (Meyer & Land, 2003) . This project involved the development of a new set of underlying concepts students should draw from the unit, application of these to the unit curriculum, and a survey of the student response to these changes. This paper reports on the threshold concepts developed for this unit, the changes this made to the unit curriculum, and a preliminary report on survey responses. Recommendations for other educators seeking to incorporate threshold concepts into their curricula are provided.

Physical activity amongst people with chronic back pain : an investigation of perceived barriers and facilitators to inform intervention development

Previous research has indicated people with non-specific low back pain who are physically inactive face a poorer prognosis than people with back pain who participate in low or moderate intensity physical activity. They also face a greater risk of other lifestyle related health conditions, such as diabetes and heart disease. For these reasons, contemporary non-surgical interventions for low back pain aim to incorporate a return to physical activity. However, there is a lack of empirical evidence supporting physical activity interventions for this purpose. It is likely that people with low back pain face additional challenges when trying to commence (or return to) regular physical activity. This exploratory qualitative research aimed to map out perceived barriers and facilitators to undertaking physical activity among people with non-specific low back pain to inform future intervention development.

Pain management

Regardless of the setting in which they work, nurses are responsible for the assessment and management of clients with pain. Pain is a key consideration in all patient care, and nurses play a critical role in pain management. Indeed, throughout history nurses have made important contributions to our understanding and management of pain through research and clinical practice. This chapter aims to provide an introduction to some key concepts in pain management and to encourage you to reflect on some of your own assumptions about pain.

The other side of the threshold : Strindberg's experiments in creative dissection

A 1500-word review of Strindberg: A Life by Sue Prideaux (Yale UP, 2012). One way of classifying biographies is to divide them into those that apply their own interpretative framework – be it psychoanalytic, gender-based, socio-historical, and so on – to a given subject and those that aim to meet the subject, on their own terms, or at least in terms that the subject would recognise...

The prevalence and perception of pain amongst hospital in-patients

The aim of this paper is to describe the prevalence and perceptions of pain and pain management amongst hospital in-patients. A cross-sectional descriptive survey of 205 patients was conducted. Presence and severity of pain was assessed using verbal descriptor and visual analogue scales, and perceptions of pain were assessed using multi-item scales. Although the severity of pain reported was consistent across age groups and clinical areas, women in the study sample were significantly more likely to report high levels of pain than men. Differences in how men and women communicate their pain were observed, with women indicating that they were less willing to ask for help with their pain. Results suggest that pain continues to be an important problem for a large number of men and women in hospital, and that the experience of pain impacts negatively upon their well-being. Gender differences in the experience of and response to pain remain important considerations for clinical nurses who have major responsibilities for the management of pain in hospitalized patients.

An intervention study to improve pain management by nurses : normative beliefs and perceived control

Based on a predictive model of nurses' intentions regarding pain management, an intervention was developed to improve nurses' pain management. The intervention involved a series of workshops with cohorts of nurses working in acute care wards to address the important antecedents to their intentions: normative beliefs and perceived control. Pre- and post-intervention measures demonstrate the effectiveness of the intervention. The effectiveness of this intervention in improving the management of patients' pain is compared with a patient education program group and a control group. The findings provide support for further developing interventions based on the theory of planned behavior.

Effect of attitudes, subjective norms and perceived control on nurses' intention to assess patients' pain

This study examines the underlying determinants of nurses' behaviour regarding the conduct of pain assessments. One hundred nurses in a variety of health care facilities were invited to complete an Attitude Intention Questionnaire based upon the theory of planned action which is an extension of the theory of reasoned action. Results provide some support for the theory of planned action, as nurses' intention to conduct pain assessment was shown to be predicted by attitude, subjective norms and perceived control, although the latter was the only variable to make an independent contribution to intention. Additional support for the importance of perceived control was provided by the analysis of 'intenders' and 'non-intenders' (to conduct pain assessments), as perceived control was the only variable which differed significantly between the groups. The findings are consistent with earlier studies which showed that the variables in the theory of planned behaviour provided reasonably accurate predictions of behavioural intention.

Effects of schedule pressure on construction performance

Accelerating a project can be rewarding. The consequences, however, can be troublesome if productivity and quality are sacrificed for the sake of remaining ahead of schedule, such that the actual schedule benefits are often barely worth the effort. The tradeoffs and paths of schedule pressure and its causes and effects are often overlooked when schedule decisions are being made. This paper analyses the effects that schedule pressure has on construction performance, and focuses on tradeoffs in scheduling. A research framework has been developed using a causal diagram to illustrate the cause-and-effect analysis of schedule pressure. An empirical investigation has been performed by using survey data collected from 102 construction practitioners working in 38 construction sites in Singapore. The results of this survey data analysis indicate that advantages of increasing the pace of work—by working under schedule pressure—can be offset by losses in productivity and quality. The negative effects of schedule pressure arise mainly by working out of sequence, generating work defects, cutting corners, and losing the motivation to work. The adverse effects of schedule pressure can be minimized by scheduling construction activities realistically and planning them proactively, motivating workers, and by establishing an effective project coordination and communication mechanism.

Combustion products of bulk aluminum rods burning in high pressure oxygen

Characterization of the combustion products released during the burning of commonly used engineering metallic materials may aid in material selection and risk assessment for the design of oxygen systems. The characterization of combustion products in regards to size distribution and morphology gives useful information for systems addressing fire detection. Aluminum rods (3.2-mm diameter cylinders) were vertically mounted inside a combustion chamber and ignited in pressurized oxygen by resistively heating an aluminum/palladium igniter wire attached to the bottom of the test sample. This paper describes the experimental work conducted to establish the particle size distribution and morphology of the resultant combustion products collected after the burning was completed and subsequently analyzed. In general, the combustion products consisted of a re-solidified oxidized slag and many small hollow spheres of size ranging from about 500 nm to 1000 µm in diameter, surfaced with quenched dendritic and grain-like structures. The combustion products were characterized using optical and scanning electron microscopy.

Social signal processing for pain monitoring using a hidden conditional random field

utomatic pain monitoring has the potential to greatly improve patient diagnosis and outcomes by providing a continuous objective measure. One of the most promising methods is to do this via automatically detecting facial expressions. However, current approaches have failed due to their inability to: 1) integrate the rigid and non-rigid head motion into a single feature representation, and 2) incorporate the salient temporal patterns into the classification stage. In this paper, we tackle the first problem by developing a “histogram of facial action units” representation using Active Appearance Model (AAM) face features, and then utilize a Hidden Conditional Random Field (HCRF) to overcome the second issue. We show that both of these methods improve the performance on the task of pain detection in sequence level compared to current state-of-the-art-methods on the UNBC-McMaster Shoulder Pain Archive.

Inter-cycle variability of in-cylinder pressure parameters in an ethanol fumigated common rail diesel engine

The effects of ethanol fumigation on the inter-cycle variability of key in-cylinder pressure parameters in a modern common rail diesel engine have been investigated. Specifically, maximum rate of pressure rise, peak pressure, peak pressure timing and ignition delay were investigated. A new methodology for investigating the start of combustion was also proposed and demonstrated—which is particularly useful with noisy in-cylinder pressure data as it can have a significant effect on the calculation of an accurate net rate of heat release indicator diagram. Inter-cycle variability has been traditionally investigated using the coefficient of variation. However, deeper insight into engine operation is given by presenting the results as kernel density estimates; hence, allowing investigation of otherwise unnoticed phenomena, including: multi-modal and skewed behaviour. This study has found that operation of a common rail diesel engine with high ethanol substitutions (>20% at full load, >30% at three quarter load) results in a significant reduction in ignition delay. Further, this study also concluded that if the engine is operated with absolute air to fuel ratios (mole basis) less than 80, the inter-cycle variability is substantially increased compared to normal operation.