Thermal control of high pressure die casting using computational fluid dynamics

The quality of high pressure die castings is a function of many interdependent parameters. It has been observed that many defects detected in the HPDC castings can be tracked back to poor die temperature distribution in the critical areas. It has therefore been recommended that the development of a technique to directly control the critical features - making them less sensitive to thermal related parameters - be very beneficial to the HPDC industry. From the information obtained from thermal image (processing), computational fluid dynamics has been applied to design the layout of internal cooling system and assign the flow conditions such as flow rate and pressure of the cooling water. it is observed that CFD prediction provides an excellent insight into the thermal balance of the high pressure die casting.

Critical factors for electronic commerce success in small business : a meta study

Small to medium-sized enterprises (SMEs) contribute significantly to the national economies and to the employment levels of different countries and represent a viable source for inventions and innovations. The recent emergence of electronic commerce in the early nineties could provide different opportunities to the small business sector to overcome its inadequacies. However, in view of the electronic commerce/business (EC) literature in organisations in general and in SMEs specifically, it was observed that EC research is scarce. Therefore, this research attempts, by reviewing relevant EC literature, to develop deeper understanding about the factors influencing EC success in SMEs. The researcher found the following issues significantly influence EC success in SMEs: e-Value, e-Cost, e-Transformation, e-Product, e-Nvolvement, e-Nnovativeness, e-Competition, external e-Support, and e-Pressure. These factors are of importance to researchers, SMEs, professionals including educational institutions and policymakers in driving SMEs and EC forward.

Playing a critical role: experiential learning resources and analytical media studies in higher education

This article compares two Information and Communication Technologies (ICTs) used in the Faculty of Arts, Deakin University Australia, and investigates the relationships between technology, pedagogy and key issues in the teaching and practice of public relations, in a media studies context. The online role-play ‘Save Wallaby Forest’ and the e-simulation ‘PRessure Point! Getting Framed (GF), in their different ways, afford learning  environments with capabilities that present public relations and media students with opportunities to discover a critical consciousness, break out of naturalised world-views, and explore alternative approaches to organisational communication. Furthermore, they present students with complex ethical issues to investigate based around the idea that media industries are powerful discursive producers and reproducers of social norms, values and beliefs which in turn shape notions of identity and influence the formation of public opinion in society (Fairclough 1999; Habermas 1995). This article explores the intersections and differences between these distinct ICTs in their relationships to a constructivist learning approach and ethical questions about how public relations both produces and reproduces world views through practice. This interacting nexus – between technology, pedagogy and theme – is significant because “what happens in the learning process” relates to the learning outcome and therefore has the potential to develop holistic reflexivity in studies of public relations (Laurillard 2003, p.42).

Squeeze pin implementation in a high pressure die casting

This paper discusses the implementation of hydraulically operated squeeze pins to reduce porosity formation in cast aluminium bearing caps. Two complete sets are cast in an eight-cavity die with a 2000t cold chamber high pressure die casting machine. The initial die configuration used a sliding core assembly with stationary pins to core a through hole in a thick section of the front cam caps. This configuration resulted in high post machining scrap rates, primarily due to porosity associated with solidification shrinkage. Replacement of the sliding core assembly with a squeeze pin unit substantially reduced shrinkage porosity in the critical region, with consequent reductions in the scrap rate. The squeeze pins are actuated 1.5s after the piston reaches the high shot changeover position, but can be successfully engaged between I and 3.5 seconds after high shot changeover. Density measurements and visual inspection confirmed the substantial improvement in porosity levels in the critical region of the castings.

The effects of time pressure and experience on nurses' risk assessment decisions : a signal detection analysis

Background: Time pressure and, occasionally, suboptimal assessment decisions are features of nursing in acute care.

Objectives: To explore the effect of generic and specialist clinical experience on the ability to detect the need to take action in acute care and the impact of time pressure on nurses' decision-making performance.

Methods: Experienced acute care registered nurses (n = 241) were presented with 50 vignettes of real clinical risk assessments. Each vignette contained seven information cues. In response to these vignettes, nurses had to decide whether to intervene or not. The 26 vignettes were time limited and mixed randomly into the 50 cases. Signal detection analysis was used to establish nurses' performance, personal decision thresholds ([beta]), and their abilities (d') to distinguish a signal of clinical risk from the clinical noise of noncontributory information.

Results: Nurses had significantly lower d' and were significantly less likely to indicate intervening under time pressure. For ability-but not threshold-there was a significant interaction of time pressure and years of experience in acute care. With no time pressure, d' increased in line with years of experience. Under time pressure, there was no effect.

Discussion: Time pressure reduced nurses' ability to detect the need and the tendency to report intervening. Thus, there were more failures to report appropriate intervention under time pressure, and the positive effects of clinical experience were negated under time pressure. More and larger scale research on the effect on clinical outcomes of time pressured nursing choices is required.

Nurses' critical event risk assessments : a judgement analysis

Aims. To explore and explain nurses' use of readily available clinical information when deciding whether a patient is at risk of a critical event.

Background. Half of inpatients who suffer a cardiac arrest have documented but unacted upon clinical signs of deterioration in the 24 hours prior to the event. Nurses appear to be both misinterpreting and mismanaging the nursing-knowledge 'basics' such as heart rate, respiratory rate and oxygenation. Whilst many medical interventions originate from nurses, up to 26% of nurses' responses to abnormal signs result in delays of between one and three hours.

Methods. A double system judgement analysis using Brunswik's lens model of cognition was undertaken with 245 Dutch, UK, Canadian and Australian acute care nurses. Nurses were asked to judge the likelihood of a critical event, 'at-risk' status, and whether they would intervene in response to 50 computer-presented clinical scenarios in which data on heart rate, systolic blood pressure, urine output, oxygen saturation, conscious level and oxygenation support were varied. Nurses were also presented with a protocol recommendation and also placed under time pressure for some of the scenarios. The ecological criterion was the predicted level of risk from the Modified Early Warning Score assessments of 232 UK acute care inpatients.

Results. Despite receiving identical information, nurses varied considerably in their risk assessments. The differences can be partly explained by variability in weightings given to information. Time and protocol recommendations were given more weighting than clinical information for key dichotomous choices such as classifying a patient as 'at risk' and deciding to intervene. Nurses' weighting of cues did not mirror the same information's contribution to risk in real patients. Nurses synthesized information in non-linear ways that contributed little to decisional accuracy. The low-moderate achievement (Ra) statistics suggests that nurses' assessments of risk were largely inaccurate; these assessments were applied consistently among 'patients' (scenarios). Critical care experience was statistically associated with estimates of risk, but not with the decision to intervene.

Conclusion. Nurses overestimated the risk and the need to intervene in simulated paper patients at risk of a critical event. This average response masked considerable variation in risk predictions, the need for action and the weighting afforded to the information they had available to them. Nurses did not make use of the linear reasoning required for accurate risk predictions in this task. They also failed to employ any unique knowledge that could be shown to make them more accurate. The influence of time pressure and protocol recommendations depended on the kind of judgement faced suggesting then that knowing more about the types of decisions nurses face may influence information use.

Relevance to clinical practice. Practice developers and educators need to pay attention to the quality of nurses' clinical experience as well as the quantity when developing judgement expertise in nurses. Intuitive unaided decision making in the assessment of risk may not be as accurate as supported decision making. Practice developers and educators should consider teaching nurses normative rules for revising probabilities (even subjective ones) such as Bayes' rule for diagnostic or assessment judgements and also that linear ways of thinking, in which decision support may help, may be useful for many choices that nurses face. Nursing needs to separate the rhetoric of 'holism' and 'expertise' from the science of predictive validity, accuracy and competence in judgement and decision making.

Crash investigation of side intrusion beam during high and low pressure tube hydroforming

Advanced high strength steels (AHSS), in particular, are an attractive group materials, offering higher strength for improved energy absorption and the opportunity to reduce weight through the use of thinner gauges. High pressure tube hydroforming (HPTH) has been used to produce safety components for these steels, but it is expensive. Low pressure tube hydroforming (LPTH) is a lower cost alternative to form the safety components in the car. The side intrusion beam is the second most critical part after front rail in the car structure for passenger safety during crash. The forming as well as crash behaviour of a square side intrusion beam from both processes was investigated using numerical simulation. This paper investigated the interaction between the forming and crash response of these materials in order to evaluate their potential for use in vehicle design for crashworthiness. The energy absorption characteristics of the different tubes were calculated and the results from the numerical analyses compared for both hydroforming process.

Coping under pressure : strategies for maintaining confidence amongst South African soccer coaches

Sport coaching can be a fulfilling and rewarding occupation, but can also be stressful because of the demands and expectations of various external factors. The complex and extraordinary demands placed on coaches, force them to perform multiple roles (e.g. educator, motivator, counsellor, adviser, trainer, manager and administrator). Soccer coaches face a number of challenges, frustrations, conflicts and tensions, the enormity of which is often underestimated. This notion is supported by the description of coaching as a perilous occupation in which coaches experience pressures like stress, conflict and tension, media pressure and intrusions into family life. This study explored the perceptions of South African soccer coaches in terms of the mechanisms they use to cope with potential stressors experienced in their jobs and employed a non-experimental design, using a quantitative approach, to assess stress and coping strategies of South African coaches. One hundred and twelve soccer coaches, coaching at the provincial level and higher, completed a questionnaire on stress and stress coping mechanisms used in their coaching jobs. Descriptive data analysis was completed using the Statistical Package for Social Sciences (SPSS – version 16). The sources of stress experienced and coping methods used by the coaches were evaluated. Results revealed that the top three sources of stress were a lack of resources, fixture backlog and games where the outcome is critical, whilst the lowest three sources of stress were political interference, physical assaults from players and substituting a player. Moreover, various coping strategies used by the coaches showed that an average of 5.68%, 5.14% and 89.78% of the sample used maladaptive coping, emotion management coping and problem management coping strategies respectively. Academic and practical implications of the study results are discussed.

Arg1098 is critical for the chloride dependence of human angiotensin I-converting enzyme C-domain catalytic activity

Angiotensin (Ang) I-converting enzyme (ACE) is a Zn²+ metalloprotease with two homologous catalytic domains. Both the N- and C-terminal domains are peptidyl dipeptidases. Hydrolysis by ACE of its decapeptide substrate Ang I is increased by Cl−, but the molecular mechanism of this regulation is unclear. A search for single substitutions to Gln among all conserved basic residues (Lys/Arg) in human ACE C-domain identified R1098Q as the sole mutant that lacked Cl− dependence. Cl−dependence is also lost when the equivalent Arg in the N-domain, Arg⁵⁰⁰, is substituted with Gln. The Arg¹⁰⁹⁸ to Lys substitution reduced Cl− binding affinity by ∼100-fold. In the absence of Cl−, substrate binding affinity (1/K m) of and catalytic efficiency (k cat/K m) for Ang I hydrolysis are increased 6.9- and 32-fold, respectively, by the Arg¹⁰⁹⁸ to Gln substitution, and are similar (<2-fold difference) to the respective wild-type C-domain catalytic constants in the presence of optimal [Cl−]. The Arg¹⁰⁹⁸ to Gln substitution also eliminates Cl− dependence for hydrolysis of tetrapeptide substrates, but activity toward these substrates is similar to that of the wild-type C-domain in the absence of Cl−. These findings indicate that: 1) Arg¹⁰⁹⁸ is a critical residue of the C-domain Cl−-binding site and 2) a basic side chain is necessary for Cl− dependence. For tetrapeptide substrates, the inability of R1098Q to recreate the high affinity state generated by the Cl−-C-domain interaction suggests that substrate interactions with the enzyme-bound Cl− are much more important for the hydrolysis of short substrates than for Ang I. Since Cl− concentrations are saturating under physiological conditions and Arg¹⁰⁹⁸ is not critical for Ang I hydrolysis, we speculate that the evolutionary pressure for the maintenance of the Cl−-binding site is its ability to allow cleavage of short cognate peptide substrates at high catalytic efficiencies.

Implications of short and long term critical flux experiments for laboratory-scale MBR operations

This paper evaluates the critical flux obtained by different techniques including tests with different flux step lengths (20 and 40 min and 7 days) and modes of operation (continuous and intermittent) under low and high MLSS concentrations. The paper also analyses a couple of long-term tests (flow rate of 40 and 20 L/day) to obtain the time required to reach the critical flux experimentally and compares those values with the results obtained numerically from a mathematical model. It was found that intermittent mode with membrane relaxation was useful in controlling the fouling of membrane and in restoring the membrane from fouling at lower MLSS.

The teacher educator as (re)negotiated professional : critical incidents in steering between state and market in Australia

A dominant discourse in western higher education circles is currently concerned— even obsessed—with the marketisation of knowledge as a commodity to be purchased and traded [Healy (1998); Poole (1998); Richardson (1998)]. These developments are broadly allied with managerial changes that some have called ‘steering at a distance’ [Kickert (1991); Marceav (1993)] whereby the control by the state of individual higher education workers is maintained and intensified at the same time that pressure is applied to 'wean' universities from government funding. This paper explores a different kind of 'steering', the kind that is being engaged by Australian teacher educators confronted by developing competitiveness in higher education. We argue that these changes compel teacher educators to (re)negotiate their professionalisms; to re-examine their attitudes towards, and values within, education and its practices as they (individually and collectively) steer new courses through the state and the market. We illustrate our argument by referring to three critical incidents in the professional lives of teacher educators located within a globalised, multi-campus and provincial Australian university, yet with important implications also for teacher educators outside Australia. We posit the (re)negotiated professionalisms manifested in those incidents as a few among several potential kinds of steering by Australian teacher educators.

Critical pre-implementation elements in engendering change for sustainability in SMEs : insights from SME sustainability leaders

Despite the increased awareness surrounding sustainability issues and growing pressure on businesses to adopt sustainable business practices, there is little understanding of management processes and practices necessary for SMEs to implement environmental sustainable (ES) practices. Through qualitative in-depth interviews, this paper draws on the experiences and perspectives from twelve SME sustainability leaders to present answers to the 'what' and 'why' of critical pre-implementation elements in engendering change for sustainability within the SME context. The research questions examined in this study are: In the views of SME sustainability leaders: what pre-implementation elements are important in setting the foundations of ES success in SMEs; what are the most important elements in the decision to introduce and encourage improved ES practices; and how do SME sustainability leaders plan for ES change in their firms. We also examine how the pre-implementation elements identified in this study, fit with the steps of one of the most well-known sustainability change management frameworks by Dunphy et al (2003). The results show that elements playing a role in setting the foundations for ES success in participating firms include: the SME leader challenging the status quo, gathering of initial information; clarifying the internal know-how about ES, identifying who the ES leader(s) is, and what the associated roles are; creating a theme of environmental sustainability in the firm (what sustainability means to the firm); and the personal mindset of leaders regarding ES. In addition, it was evident from the interview data that apart from providing valuable data regarding what must change and why, the drivers and benefits of ES provide a strong rationale and motivation to the rest of the organisation why sustainability is important to the organisation. Furthermore, it is evident from the interview data that the most used strategic approach to planning by SME sustainability leaders, is a deliberate approach even though the emergent approach to planning has also featured in some SMEs. Furthermore, the CEOs are the main players in the strategic process, with the majority involving staff in planning for ES. The results also indicate that in matching the pre-implementation elements to Dunphy et al‘s (2003) sustainability change management steps, the execution of two of their steps may need adjustment to be fully applicable to SMEs. Several practical implications for other SMEs are outlined. In conclusion, the framework outlined in this paper provides an example of a critically reflective approach to a specific phase of the environmental sustainability puzzle in SMEs.

Trench stability under bentonite pressure in purely cohesive clay

Trench stability is a conventional geotechnical problem; however, current evaluations are often based entirely on empiricism. This paper uses numerical finite-element upper and lower bound limit analysis to produce stability charts for two-dimensional and three-dimensional homogeneous and inhomogeneous undrained diaphragm wall trenches. Using the limit theorems cannot only provide a simple and useful way of analyzing the stability of the trench, but also avoid the shortcomings and arbitrary assumptions underpinning the limit equilibrium method. By considering the effects from the bentonite slurry pressures, the collapse load in this study has been bracketed to within ±8.5 or better by the numerical upper and lower bound limit analyses. The chart solutions can be used to predict either the critical depth or the safety factor of the trench and provide a convenient tool for preliminary designs by practicing engineers. © 2014 American Society of Civil Engineers.

INTroducing a care bundle to prevent pressure injury (INTACT) in at-risk patients: a protocol for a cluster randomised trial

BACKGROUND: Pressure injuries are a significant clinical and economic issue, affecting both patients and the health care system. Many pressure injuries in hospitals are facility acquired, and are largely preventable. Despite growing evidence and directives for pressure injury prevention, implementation of preventative strategies is suboptimal, and pressure injuries remain a serious problem in hospitals. OBJECTIVES: This study will test the effectiveness and cost-effectiveness of a patient-centred pressure injury prevention care bundle on the development of hospital acquired pressure injury in at-risk patients. DESIGN: This is a multi-site, parallel group cluster randomised trial. The hospital is the unit of randomisation. METHODS: Adult medical and surgical patients admitted to the study wards of eight hospitals who are (a) deemed to be at risk of pressure injury (i.e. have reduced mobility), (b) expected to stay in hospital for ≥48h, (c) admitted to hospital in the past 36h; and (d) able to provide informed consent will be eligible to participate. Consenting patients will receive either the pressure injury prevention care bundle or standard care. The care bundle contains three main messages: (1) keep moving; (2) look after your skin; and (3) eat a healthy diet. Nurses will receive education about the intervention. Patients will exit the study upon development of a pressure injury, hospital discharge or 28 days, whichever comes first; transfer to another hospital or transfer to critical care and mechanically ventilated. The primary outcome is incidence of hospital acquired pressure injury. Secondary outcomes are pressure injury stage, patient participation in care and health care costs. A health economic sub-study and a process evaluation will be undertaken alongside the trial. Data will be analysed at the cluster (hospital) and patient level. Estimates of hospital acquired pressure injury incidence in each group, group differences and 95% confidence interval and p values will be reported. DISCUSSION: To our knowledge, this is the first trial of an intervention to incorporate a number of pressure injury prevention strategies into a care bundle focusing on patient participation and nurse-patient partnership. The results of this study will provide important information on the effectiveness and cost-effectiveness of this intervention in preventing pressure injuries in at-risk patients. If the results confirm the utility of the developed care bundle, it could have a significant impact on clinical practice worldwide. TRIAL REGISTRATION: This trial is registered with the Australian New Zealand Clinical Trials Registry, ACTRN12613001343796.

Amine enrichment of thin-film composite membranes via low pressure plasma polymerization for antimicrobial adhesion

Thin-film composite membranes, primarily based on poly(amide) (PA) semipermeable materials, are nowadays the dominant technology used in pressure driven water desalination systems. Despite offering superior water permeation and salt selectivity, their surface properties, such as their charge and roughness, cannot be extensively tuned due to the intrinsic fabrication process of the membranes by interfacial polymerization. The alteration of these properties would lead to a better control of the materials surface zeta potential, which is critical to finely tune selectivity and enhance the membrane materials stability when exposed to complex industrial waste streams. Low pressure plasma was employed to introduce amine functionalities onto the PA surface of commercially available thin-film composite (TFC) membranes. Morphological changes after plasma polymerization were analyzed by SEM and AFM, and average surface roughness decreased by 29%. Amine enrichment provided isoelectric point changes from pH 3.7 to 5.2 for 5 to 15 min of plasma polymerization time. Synchrotron FTIR mappings of the amine-modified surface indicated the addition of a discrete 60 nm film to the PA layer. Furthermore, metal affinity was confirmed by the enhanced binding of silver to the modified surface, supported by an increased antimicrobial functionality with demonstrable elimination of E. coli growth. Essential salt rejection was shown minimally compromised for faster polymerization processes. Plasma polymerization is therefore a viable route to producing functional amine enriched thin-film composite PA membrane surfaces.