449 resultados para INFLUENCE DIAGNOSTICS


Relevância:

20.00% 20.00%

Publicador:

Resumo:

Diagnostics is based on the characterization of mechanical system condition and allows early detection of a possible fault. Signal processing is an approach widely used in diagnostics, since it allows directly characterizing the state of the system. Several types of advanced signal processing techniques have been proposed in the last decades and added to more conventional ones. Seldom, these techniques are able to consider non-stationary operations. Diagnostics of roller bearings is not an exception of this framework. In this paper, a new vibration signal processing tool, able to perform roller bearing diagnostics in whatever working condition and noise level, is developed on the basis of two data-adaptive techniques as Empirical Mode Decomposition (EMD), Minimum Entropy Deconvolution (MED), coupled by means of the mathematics related to the Hilbert transform. The effectiveness of the new signal processing tool is proven by means of experimental data measured in a test-rig that employs high power industrial size components.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In the field of diagnostics of rolling element bearings, the development of sophisticated techniques, such as Spectral Kurtosis and 2nd Order Cyclostationarity, extended the capability of expert users to identify not only the presence, but also the location of the damage in the bearing. Most of the signal-analysis methods, as the ones previously mentioned, result in a spectrum-like diagram that presents line frequencies or peaks in the neighbourhood of some theoretical characteristic frequencies, in case of damage. These frequencies depend only on damage position, bearing geometry and rotational speed. The major improvement in this field would be the development of algorithms with high degree of automation. This paper aims at this important objective, by discussing for the first time how these peaks can draw away from the theoretical expected frequencies as a function of different working conditions, i.e. speed, torque and lubrication. After providing a brief description of the peak-patterns associated with each type of damage, this paper shows the typical magnitudes of the deviations from the theoretical expected frequencies. The last part of the study presents some remarks about increasing the reliability of the automatic algorithm. The research is based on experimental data obtained by using artificially damaged bearings installed in a gearbox.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This article examines the role of informal kinship care in addressing the emotional needs and mental health, along with relationships, of school-age children left behind in rural China. Rural–urban migration in China has caused many rural children to be left behind in their local communities. Based on semi-structured interview data, this article explores Confucianism’s impact on Chinese kin caregivers’ understandings of children’s needs and their childrearing practices to address these needs. Through the lens of attachment theory, this study identified a close affective bond between children left behind and their kin caregivers. This relationship is underpinned by kin caregivers’ high commitment and love for children, and the Confucian concept of ‘benevolence’. It not only provides children left behind with a sense of belonging, it also alleviates their trauma/grief due to separation from their parents

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Statistics on health care workers' occupational exposures to bloodborne pathogens underestimate the true extent of the problem because of a tendency for underreporting. A descriptive correlational design was used to investigate compliance with standard precautions and occupational exposure reporting practices among perioperative nurses in Australia. The study found that although intention to report both percutaneous and mucocutaneous exposures was relatively high, mean compliance rates for actually reporting exposures incurred were considerably lower. The perception of barriers to reporting significantly influenced compliance.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

"Food literacy" has emerged as a term to describe the everyday practicalities needed for healthy eating. It is increasingly used in policy, practice, research and in the public arena. This thesis empirically defined the term, identified its components, and developed models of its relationship to nutrition and health. Food literacy was examined from two perspectives; that of food experts and that of individuals using the case study of young people experiencing disadvantage. The research provides a common language and conceptualisation of food literacy which is being used by governments, policy-makers and practitioners to guide investment and practice.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Australian cities are particularly vulnerable to climate change. Adapting to climate change is a critical task for contemporary spatial planning, one that is widely recognised by the planning profession and beginning to receive substantive attention in planning policy. However adaptation takes place within the context of established spatial governance regimes and planning cultures, and examples of effective adaptation are often grounded in progressive contexts markedly different than Australia. In Australia, planning is subject to strong neoliberal reform agendas (Gleeson & Low, 2000a, 2000b) and national adaptation policies align with neoliberal views (Granberg & Glover, 2011). Planning in Queensland has been subject to deregulation (Buxton et al., 2012) and the continued influence of neoliberalism (Wright & Cleary, 2012). The influence of neoliberalism on climate change adaptation has received little consideration in research and literature. This paper reviews a case study of adaptation planning through the lens of the recent and contemporary influences of neoliberalism. It examines spatial/land-use planning for climate change adaptation in Queensland, identifying the underlying rationales, priorities and strategies. A justification for such an investigation is advanced based on the challenges to planning facilitating adaptation and identified links to neoliberalism. A preliminary analysis of interviews with planners is then used to identify and discuss the ideological influences practitioners perceive in current approaches to adaptation in Queensland and the implications of such.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Aim To develop and psychometrically test the Barriers to Nurses’ use of Physical Assessment Scale. Background There is growing evidence of failure to recognise hospitalised patients at risk of clinical deterioration, in part due to inadequate physical assessment by nurses. Yet, little is known about the barriers to nurses’ use of physical assessment in the acute hospital setting and no validated scales have been published. Design Instrument development study. Method Scale development was based on a comprehensive literature review, focus groups, expert review and psychometric evaluation. The scale was administered to 434 acute care registered nurses working at a large Australian teaching hospital between June and July 2013. Psychometric analysis included factor analysis, model fit statistics and reliability testing. Results The final scale was reduced to 38 items representing seven factors, together accounting for 57.7% of the variance: (1) reliance on others and technology, (2) lack of time and interruptions, (3) ward culture, (4) lack of confidence, (5) lack of nursing role models, (6) lack of influence on patient care, and; (7) specialty area. Internal reliability ranged from .70 to .86. Conclusion Findings provide initial evidence for the validity and reliability of the Barriers to Nurses’ use of Physical Assessment Scale and point to the importance of understanding the organisational determinants of nurses’ assessment practices. The new scale has potential clinical and research applications to support nursing assessment in acute care settings.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Contemporary nutrition policies and plans call for focussing efforts to improve nutrition through a closer connection with food and the everyday practicalities of how people live and eat. Various words have been used to articulate what this might mean in practice. More recently, the term “food literacy” has emerged to explain this gap between the policy aims the (in)ability of people to know, understand and use food to meet nutrition recommendations. Despite its increasing use, there is no common understanding of this term or its components. Once established, food literacy could be measured in order to examine its association with nutritional outcomes. A Delphi study of 43 Australian food experts from diverse sectors and settings explored their understanding of the term “food literacy”, the likely components and possible relationship with nutrition. The three round Delphi study began with a semi-structured telephone interview and was followed by two online surveys. Constructivist grounded theory was used to analyse data, from which a conceptual model of the relationship between food literacy and nutrition was developed. The model was then tested and refined following a phenomenological study of 37 young people aged 16-25 years who were responsible for feeding themselves. They were interviewed about their food intake, day-to-day food decision making, the knowledge and skills used and their perceptions of someone who is “good with food”. Analysis from the Delphi study identified, eighty components of food literacy and these were grouped into eight domains: 1)access, 2)planning and management, 3)selection, 4)knowing where food comes from, 5)preparation, 6)eating, 7)nutrition and 8)food related language. When these were compared to results of the Young People’s study it was found that while specific components of food literacy were largely contextual, the importance of all eight domains continued to be relevant. The results of these qualitative studies have set the boundaries and scope of meaning of food literacy and will be used to inform the development of measurable variables to be tested in a quantitative cross-sectional study. This prospective study will examine the relationship between food literacy and nutrition. This research is useful in guiding government strategy and investment, and informing the planning, implementation and evaluation of interventions by practitioners.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Research on the achievement and retention of female students in science and mathematics is located within a context of falling levels of participation in physical science and mathematics courses in Australian schools, and underrepresentation of females in some science, technology, engineering and mathematics (STEM) courses. The Interests and Recruitment in Science (IRIS) project is an international project that aims to contribute to understanding and improving recruitment, retention and gender equity in STEM higher education. Nearly 3500 first year students in 30 Australian universities responded to the IRIS survey of 5-point Likert items and open responses. This paper explores gender differences in first year university students’ responses to three questions about important influences on their course choice. The IRIS study found good teachers were rated highly by both males and females as influential in choosing STEM courses, and significantly higher numbers of females rated personal encouragement from senior high school science teacher as very important. In suggestions for addressing sex disparities in male-dominated STEM courses, more females indicated the importance of good teaching/encouragement and more females said (unspecified) encouragement. This study relates to the influence of school science teachers and results are discussed in relation to implications for science education.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This paper reports results from a study comparing teachers’ and students’ perceptions about the relative degree of influence parents, teachers, friends, older students and careers advisors have on students’ decisions about enrolling in non-compulsory high school science subjects. The comparison was carried out as part of the Choosing Science project - a large-scale Australian study of 15 year-old students’ experiences of school science and intentions regarding further participation. The study found that students considered their science teachers to have had the greatest influence, followed by parents and then friends. In contrast, however, science teachers believed their students to be most influenced in their decisions by friends and peers, followed by older students and siblings and parents, with teachers themselves having relatively little influence. Both groups believed that advice from careers advisors was of little influence. The findings are unique in the science education literature in providing an insight into differences and similarities in the perceptions of students and their teachers. In particular they indicate that teachers play a far greater role in students’ decisions about enrolling in science than they believe. This has important implications for science teachers and teacher educators in terms of appreciating their influence and applying it in ways that encourage participation in science courses.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Frequency Domain Spectroscopy (FDS) is used to assess the insulation condition of oil-paper power transformers. Dissipation factor is one of the conventional indicators to analyze insulation ageing status. In this paper, the imaginary admittance of the transformers insulation, after removal of the geometric capacitance, is proposed as an alternative indicator to assist in the interpretation of ageing status. Ageing effects on the imaginary admittance are investigated both through simulation results and experimental results.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

To obtain accurate Monte Carlo simulations of small radiation fields, it is important model the initial source parameters (electron energy and spot size) accurately. However recent studies have shown that small field dosimetry correction factors are insensitive to these parameters. The aim of this work is to extend this concept to test if these parameters affect dose perturbations in general, which is important for detector design and calculating perturbation correction factors. The EGSnrc C++ user code cavity was used for all simulations. Varying amounts of air between 0 and 2 mm were deliberately introduced upstream to a diode and the dose perturbation caused by the air was quantified. These simulations were then repeated using a range of initial electron energies (5.5 to 7.0 MeV) and electron spot sizes (0.7 to 2.2 FWHM). The resultant dose perturbations were large. For example 2 mm of air caused a dose reduction of up to 31% when simulated with a 6 mm field size. However these values did not vary by more than 2 % when simulated across the full range of source parameters tested. If a detector is modified by the introduction of air, one can be confident that the response of the detector will be the same across all similar linear accelerators and the Monte Carlo modelling of each machine is not required.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Tumour necrosis factor (TNF)alpha is implicated in the relationship between obesity and insulin resistance/ type 2 diabetes. In an effort to understand this association better we (i) profiled gene expression patterns of TNF, TNFR1 and TNFR2 and (ii) investigated the effects of TNF on glucose uptake in isolated adipocytes and adipose tissue explants from omental and subcutaneous depots from lean, overweight and obese individuals. TNF expression correlated with expression of TNFR2, but not TNFR1, and TNF and TNFR2 expression increased in obesity. TNFR1 expression was higher in omental than in subcutaneous adipocytes. Expression levels of TNF or either receptor did not differ between adipocytes from individuals with central and peripheral obesity. TNF only suppressed glucose uptake in insulin-stimulated subcutaneous tissue and this suppression was only observed in tissue from lean subjects. These data support a relationship between the TNF system and body mass index (BMI), but not fat distribution, and suggest depot specificity of the TNF effect on glucose uptake. Furthermore, adipose tissue from obese subjects already appears insulin 'resistant' and this may be a result of the increased TNF levels.